diff --git a/CHANGES.md b/CHANGES.md
index 38d13af..acaea68 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -51,8 +51,8 @@ Swift-Pfade relativ zu `filius-ipad/ios/FiliusPad/TopologyEditor/` (Stand
 | `test/javaBeansWriter.test.ts`, `test/beans/` | — | neu: 11 Dateien des Schreibers, von Javas `XMLDecoder` gelesen und beschrieben; Erwartungen von Hand |
 | `src/topologyWriter.ts` | Java `SzenarioVerwaltung.netzwerkSpeichern`, Konstruktoren von `NetzwerkInterface`, `Port`, `GUIKabelItem` und der Systemsoftware | neu nach Java: `konfiguration.xml` aus Javas Sicht — Geräte, Schnittstellen (vom Konstruktor angelegte über Getter, weitere per `add`), Ports über Getter-Verweise, Kabel samt Zeichen-Enden (`kabelpanel`), Doku-Elemente; Systemsoftware über ihre Setter: SSID, Lernzeit, RIP, manuelle Routen, DHCP-Client und -Server, statische NAT, Modem, Router-Firewall (über das `konfig`-Plug-in des Webservers, wie XMLEncoder sie erreicht); Dateisysteme (an die Wurzel des Konstruktors angehängt wie bei XMLEncoder, beim Router hinter dessen Vorlagen); installierte Programme nach den Dateien (Webserver, Tauschbörse und E-Mail-Server legen ihre Ordner nur an, wo sie fehlen; der DNS-Server liest `/dns/hosts` beim Installieren), je unter ihrem Schlüssel mit der Systemsoftware wie `installApp`, samt Einstellungen und persönlicher Firewall; E-Mail: Domain und Bean-Konten des Servers samt Postfächern, Ordner und Adressbuch des Clients (sein Konto steht in `/konten.txt`, einer Datei); Javas Fehler nicht übernommen: ein Empfänger, den eine ältere Datei als Zeichenkette hält, wird als der `AddressEntry` geschrieben, den Javas `AddressEntry(String)` daraus macht (Java legt die Zeichenkette ungeprüft in die typisierte Liste, sein E-Mail-Fenster scheitert daran), ein `null`-Empfänger fällt weg; Kopf „Filius version: 2.14.0 (mdg-filius)“ |
 | `test/topologyWriter.test.ts`, `test/written.java.json` | — | neu: alle 23 Korpus-Dateien gelesen und neu geschrieben, von Java geladen — Topologie, Systemsoftware, Dateisysteme und Programme samt E-Mail wie beim Original (bis auf die benannte Abweichung bei Empfängern als Zeichenkette, nur in `man-in-the-middle.fls`) (Java gegen Java); dazu eine künstliche Topologie mit dem, was der Korpus nicht hat (u. a. eingeschaltete Router-Firewall mit Regeln jedes Protokolls, alle Firewall-Schalter abseits der Vorgabe, Modem mit eigenem Port und Ziel, verschachtelter Dateibaum mit umbenannter Wurzel, namenlosem Ordner, Datei ohne Typ und Inhalt mit CR/CRLF und Zeichen jenseits der BMP, Heimrouter mit eigener Wurzel, jedes Filius-Programm mit Einstellungen abseits der Vorgabe samt persönlicher Firewall, von Java angelegte Ordner `/peer2peer` und `/mailserver`, E-Mail-Server und -Client mit Konto, Postfach, drei Ordnern, Adressbuch und Empfängern aller Formen) |
-| `src/exportProject.ts` | Gegenstück zu `importProject.ts`; Java `JHostKonfiguration.updateWifiConnection`, `InternetKnotenBetriebssystem.getStandardGateway`/`setStandardGateway` | neu: Editor-Modell → Javas Sicht für den Schreiber, Schritt X1 Topologie — Geräte, Schnittstellen (MAC wie in der Simulation: aus der Datei oder aus der Port-ID abgeleitet), Kabel samt Funk (Karte drahtlos und Switch, wie Java verbindet), Gateway und DNS an allen Schnittstellen wie Javas eigene Setter, Doku-Elemente; X2 Systemsoftware — SSIDs, Lernzeit, Routen, RIP, DHCP-Client und -Server, Portweiterleitung, Firewall (Namen des Kerns als Javas Zahlen), Modems aus den Paaren des Modells (Port aus dem Paarnamen, der erste eines Paars dient, Ziel `localhost`) |
-| `test/exportProject.test.ts`, `test/exported.java.json` | — | neu: alle 23 Korpus-Dateien importiert, exportiert, geschrieben und von Java geladen — Topologie wie beim Original bis auf benannte Abweichungen (abgeleiteter MAC und abgeleitete Switch-SSID statt gewürfelter, Modem-Rollen nach Reihenfolge im Paar, Doku in Zeichenreihenfolge mit Text, Schrift und Mindestgröße des Modells); dazu ein künstliches Modell, das Java ebenfalls lädt |
+| `src/exportProject.ts` | Gegenstück zu `importProject.ts`; Java `JHostKonfiguration.updateWifiConnection`, `InternetKnotenBetriebssystem.getStandardGateway`/`setStandardGateway` | neu: Editor-Modell → Javas Sicht für den Schreiber, Schritt X1 Topologie — Geräte, Schnittstellen (MAC wie in der Simulation: aus der Datei oder aus der Port-ID abgeleitet), Kabel samt Funk (Karte drahtlos und Switch, wie Java verbindet), Gateway und DNS an allen Schnittstellen wie Javas eigene Setter, Doku-Elemente; X2 Systemsoftware — SSIDs, Lernzeit, Routen, RIP, DHCP-Client und -Server, Portweiterleitung, Firewall (Namen des Kerns als Javas Zahlen), Modems aus den Paaren des Modells (Port aus dem Paarnamen, der erste eines Paars dient, Ziel `localhost`); X3 Dateien von Rechner und Notebook — Typ aus der Inhaltsart (Text nach Endung, sonst `text`; Bild und Binärdaten nach Medientyp), Bilder und Binärdaten in Base64 wie Filius' `Base64.encodeBytes` (Umbruch nach 76 Zeichen, an 19 Längen mit Java gemessen) |
+| `test/exportProject.test.ts`, `test/exported.java.json` | — | neu: alle 23 Korpus-Dateien importiert, exportiert, geschrieben und von Java geladen — Topologie wie beim Original bis auf benannte Abweichungen (abgeleiteter MAC und abgeleitete Switch-SSID statt gewürfelter, Modem-Rollen nach Reihenfolge im Paar, Doku in Zeichenreihenfolge mit Text, Schrift und Mindestgröße des Modells, Dateien in der Ordnung und mit dem Typ des Modells, keine eigenen Dateien von Routern); dazu ein künstliches Modell, das Java ebenfalls lädt |
 | `src/importEmail.ts` | `Persistence/TopologyProjectStore.swift` (`registerJavaEmailConfigurations`, `assignedJavaEmailMessages`) | übertragen, Eingabe ist Javas Sicht: Server-Konten aus `/mailserver/konten.txt`, ohne Datei aus der Bean-Liste (Java verlöre sie); Client-Konto aus `/konten.txt`, ohne Datei aus der älteren `kontoListe` (Filius 2.14 liest sie nicht mehr); Konten und Nachrichten bleiben, wo Swift verwirft, was seine Prüfung nicht besteht; Vor- und Nachname getrennt; Empfangszeit nur aus der Datei (Swift nummeriert); gegen Swifts Modell geprüft |
 | `test/importEmail.test.ts`, `test/email-*.swift.json` | `State/TopologyEmail.swift` (`decodeJavaServer`, `decodeJavaClient`) als Vergleich | neu: dieselben 43 Kontodateien mit Swifts Leser; wie Swift bis auf benannte Fälle, in denen Swift prüft und die ganze Datei verwirft, wo Java liest |
 | `src/javaFileSystem.ts`, `src/javaString.ts` | Java `Dateisystem.holeDatei`, `String.trim`/`split`/`equalsIgnoreCase` | neu nach Java; die Groß-/Kleinschreibung gegenüber ASCII am JDK über die ganze BMP gemessen |
diff --git a/packages/fls/src/exportProject.ts b/packages/fls/src/exportProject.ts
index 54dd4ef..cc39e84 100644
--- a/packages/fls/src/exportProject.ts
+++ b/packages/fls/src/exportProject.ts
@@ -15,7 +15,13 @@
 // model has no setting for is what Java's constructors make. A remote link
 // pair becomes modems on the port its identifier names (12345 when it names
 // none): the first of a pair in node order serves, the others connect to
-// localhost — the model's pairs live in one project. System software, files and programs
+// localhost — the model's pairs live in one project.
+//
+// The files of a PC or notebook: the model's directories and files under
+// Java's root, each file a Datei of the type Java's importer reads it by —
+// text by its extension (else "text"), an image or binary data by its media
+// type, in Base64 as FILIUS's Base64.encodeBytes writes it (javaBase64). A router or home
+// router keeps the files its constructor makes; the model holds none for it. System software, files and programs
 // follow in later steps.
 //
 // What the model keeps is written as it keeps it, and so differs from the
@@ -31,12 +37,16 @@
 //  - a documentation item always has a text and a font, bold or plain: where
 //    Java has none, the empty text and Dialog 12 the model gives it;
 //  - a switch's SSID the file lacked (Java rolls one) is the one the model
-//    derives from the node's id.
+//    derives from the node's id;
+//  - files in the model's order (directories first, then by name) and of the
+//    type their kind says, not the one the file named; a router's own files
+//    (a web server's www.conf) are not in the model.
 //
 // Checked by Java: every corpus file, imported, exported and written, loads in
 // Java FILIUS to the topology of the original up to those departures.
 
 import {
+  base64Encode,
   defaultSwitchConfiguration,
   dhcpServerConfiguration,
   effectiveMacAddress,
@@ -60,8 +70,9 @@ import {
   type NodeKind,
   type TopologyGraph,
   type TopologyNode,
+  type VirtualFileSystem,
 } from '@mdg-filius/core';
-import type { FlsDhcpServer, FlsFirewall } from './systemSoftware.js';
+import type { FlsDhcpServer, FlsFileTree, FlsFirewall } from './systemSoftware.js';
 import type { FlsDocumentationItem, FlsInterface, FlsLink, FlsNodeClass } from './topology.js';
 import type { NodeToWrite, SystemToWrite, TopologyToWrite } from './topologyWriter.js';
 
@@ -79,6 +90,7 @@ export interface ProjectToExport {
   readonly dhcpServerConfigurations: ReadonlyMap<Id, DhcpServerConfiguration>;
   readonly portForwardingRowsByNodeId: ReadonlyMap<Id, readonly GatewayPortForwardingRow[]>;
   readonly remoteLinkConfigurations: ReadonlyMap<Id, RemoteLinkConfiguration>;
+  readonly virtualFileSystems: ReadonlyMap<Id, VirtualFileSystem>;
   readonly documentationItems: readonly DocumentationItem[];
 }
 
@@ -206,7 +218,12 @@ function exportSystem(node: TopologyNode, project: ProjectToExport, servingModem
     case 'pc':
     case 'notebook': {
       const ssid = project.hostWirelessConfigurations.get(id)?.ssid ?? '';
-      return { ...system, ssid: ssid === '' ? null : ssid };
+      const files = project.virtualFileSystems.get(id);
+      return {
+        ...system,
+        ssid: ssid === '' ? null : ssid,
+        fileSystem: { kind: 'directory', name: 'root', children: files === undefined ? [] : fileTrees(files, '/') },
+      };
     }
     case 'router':
       return {
@@ -228,6 +245,50 @@ function exportSystem(node: TopologyNode, project: ProjectToExport, servingModem
   }
 }
 
+/** The text types Java's importer reads as text, named by a file's extension. */
+const TEXT_EXTENSIONS = new Set(['txt', 'html', 'htm', 'css', 'xml', 'csv', 'conf', 'log']);
+
+function fileTrees(files: VirtualFileSystem, directory: string): FlsFileTree[] {
+  return files.entries(directory).map((entry): FlsFileTree => {
+    const name = entry.path.slice(entry.path.lastIndexOf('/') + 1);
+    const file = (type: string | null, content: string): FlsFileTree => ({ kind: 'file', name, type, content, children: [] });
+    switch (entry.content.kind) {
+      case 'directory':
+        return { kind: 'directory', name, children: fileTrees(files, entry.path) };
+      case 'text': {
+        const dot = name.lastIndexOf('.');
+        const extension = dot < 0 ? '' : name.slice(dot + 1).toLowerCase();
+        return file(TEXT_EXTENSIONS.has(extension) ? extension : 'text', entry.content.text);
+      }
+      case 'image':
+        return file(subtype(entry.content.mediaType), javaBase64(entry.content.data));
+      case 'binary':
+        return file(entry.content.mediaType === undefined ? '' : subtype(entry.content.mediaType), javaBase64(entry.content.data));
+    }
+  });
+}
+
+/**
+ * FILIUS's Base64.encodeBytes (iHarder Base64 2.x): a line break after every
+ * 76 characters — also after the last full line — then the padded rest.
+ */
+export function javaBase64(bytes: Uint8Array): string {
+  const full = bytes.length - (bytes.length % 3);
+  let text = '';
+  for (let offset = 0; offset < full; offset += 57) {
+    const end = Math.min(offset + 57, full);
+    text += base64Encode(bytes.subarray(offset, end));
+    if (end - offset === 57) text += '\n';
+  }
+  return text + base64Encode(bytes.subarray(full));
+}
+
+/** "image/png" → "png", "image/jpeg" → "jpg", as Java names them. */
+function subtype(mediaType: string): string {
+  const name = mediaType.slice(mediaType.indexOf('/') + 1);
+  return name === 'jpeg' ? 'jpg' : name;
+}
+
 function exportDhcpServer(server: DhcpServerConfiguration): FlsDhcpServer {
   return {
     isActive: server.isActive,
diff --git a/packages/fls/test/base64.java.json b/packages/fls/test/base64.java.json
new file mode 100644
index 0000000..9e1b198
--- /dev/null
+++ b/packages/fls/test/base64.java.json
@@ -0,0 +1,78 @@
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+  [
+    0,
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+  ],
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+    1,
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+  [
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+  ],
+  [
+    2001,
+    "CzBVep/E6Q4zWH2ix+wRNluApcrvFDleg6jN8hc8YYar0PUaP2SJrtP4HUJnjLHW+yBFao+02f4j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\nYoes0fYb"
+  ],
+  [
+    2002,
+    "CzBVep/E6Q4zWH2ix+wRNluApcrvFDleg6jN8hc8YYar0PUaP2SJrtP4HUJnjLHW+yBFao+02f4j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\nYoes0fYbQA=="
+  ],
+  [
+    2052,
+    "CzBVep/E6Q4zWH2ix+wRNluApcrvFDleg6jN8hc8YYar0PUaP2SJrtP4HUJnjLHW+yBFao+02f4j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\n"
+  ]
+]
diff --git a/packages/fls/test/exportProject.test.ts b/packages/fls/test/exportProject.test.ts
index 50da906..10995f1 100644
--- a/packages/fls/test/exportProject.test.ts
+++ b/packages/fls/test/exportProject.test.ts
@@ -20,12 +20,14 @@ import {
   stableGeneratedMacAddress,
   type Id,
   type TopologyNode,
+  VirtualFileSystem,
 } from '@mdg-filius/core';
 import { describe, expect, it } from 'vitest';
 import {
   decodeJavaBeans,
   exportProject,
   importProject,
+  javaBase64,
   readFlsArchive,
   readTopology,
   writeFlsArchive,
@@ -66,10 +68,12 @@ const original = JSON.parse(readFileSync(join(corpusRoot, 'corpus.java.json'), '
 const exportedPath = join(here, 'exported.java.json');
 const exported = JSON.parse(readFileSync(exportedPath, 'utf8')) as Record<string, JavaFile>;
 
-/** The system software without its files and applications, later steps. */
+/** The system software without its applications, a later step; files in any order. */
 function systemOf(system: Record<string, unknown>) {
-  const { fileSystem: _files, applications: _applications, ...settings } = system;
-  return settings;
+  const { applications: _applications, ...settings } = system;
+  return settings.fileSystem === undefined || settings.fileSystem === null
+    ? settings
+    : { ...settings, fileSystem: sortedTree(settings.fileSystem as JavaTree) };
 }
 
 /** The topology of Java's view: the label's position, not its size. */
@@ -102,7 +106,15 @@ function topologyOf(view: JavaFile) {
  *    the model derives from the node's id;
  *  - modemRoles: the model keeps a pair of modems, not which one serves: the
  *    first of a pair in node order serves, the others connect. Both ways
- *    work within one project, where the client connects to localhost.
+ *    work within one project, where the client connects to localhost;
+ *  - routerFiles: the model holds no files for a router or home router; what
+ *    the file adds to the ones its constructor makes (a web server's
+ *    www.conf) is not written;
+ *  - fileTypes: a file's type follows from its kind in the model (fileType
+ *    below), not the one the file named — Java names them unevenly itself
+ *    (txt, text/txt, html, none);
+ *  - fileOrder: directories first, then by name (compared regardless of
+ *    order here).
  */
 const DEPARTURES = {
   generatedMac(view: JavaFile, macs: (string | undefined)[][]): JavaFile {
@@ -130,6 +142,25 @@ const DEPARTURES = {
       return { ...node.system, modem: { ...(node.system.modem as object), mode: serves ? 1 : 2 } };
     });
   },
+  routerFiles(view: JavaFile, added: number[]): JavaFile {
+    return mapSystems(view, (node, index) => {
+      if ((node.class !== 'Vermittlungsrechner' && node.class !== 'Gateway') || added[index] === 0) return node.system;
+      const tree = node.system.fileSystem as JavaTree;
+      return { ...node.system, fileSystem: { ...tree, children: tree.children.slice(0, tree.children.length - added[index]!) } };
+    });
+  },
+  fileTypes(view: JavaFile): JavaFile {
+    const retype = (tree: JavaTree): JavaTree => ({
+      ...tree,
+      ...('file' in tree ? { type: fileType(tree.file as string, tree.type as string | null) } : {}),
+      children: tree.children.map(retype),
+    });
+    return mapSystems(view, (node) =>
+      node.system.fileSystem === undefined || node.system.fileSystem === null
+        ? node.system
+        : { ...node.system, fileSystem: retype(node.system.fileSystem as JavaTree) },
+    );
+  },
   documentation(view: JavaFile): JavaFile {
     const items = (view.documentation as Record<string, unknown>[]).map((item) => {
       const [x, y, width, height] = item.bounds as number[];
@@ -144,6 +175,45 @@ const DEPARTURES = {
   },
 };
 
+type JavaTree = { file?: string; type?: string | null; children: JavaTree[] } & Record<string, unknown>;
+
+const IMAGE_TYPES = new Set(['png', 'jpg', 'jpeg', 'gif', 'bmp', 'image']);
+const TEXT_TYPES = new Set(['', 'text', 'txt', 'text/txt', 'html', 'htm', 'css', 'xml', 'csv', 'conf', 'log']);
+const TEXT_EXTENSIONS = new Set(['txt', 'html', 'htm', 'css', 'xml', 'csv', 'conf', 'log']);
+
+/**
+ * The type of a file in the model's kind: an image (by its type or
+ * extension) by its media type, "jpg" for JPEG; text by a known extension,
+ * else "text"; other data by its type.
+ */
+function fileType(name: string, type: string | null): string {
+  const declared = (type ?? '').trim().toLowerCase();
+  const dot = name.lastIndexOf('.');
+  const extension = dot < 0 ? '' : name.slice(dot + 1).toLowerCase();
+  if (IMAGE_TYPES.has(declared) || IMAGE_TYPES.has(extension)) {
+    const subtype = declared === 'image' || declared === '' ? (extension === '' ? 'png' : extension) : declared;
+    return subtype === 'jpeg' ? 'jpg' : subtype;
+  }
+  if (TEXT_TYPES.has(declared)) return TEXT_EXTENSIONS.has(extension) ? extension : 'text';
+  return declared;
+}
+
+/** A file tree with every directory's children in an order that does not depend on the list's. */
+function sortedTree(tree: JavaTree): JavaTree {
+  const children = tree.children.map(sortedTree);
+  return { ...tree, children: children.map((child) => JSON.stringify(child)).sort().map((text) => JSON.parse(text) as JavaTree) };
+}
+
+/** Every node's file tree as text, sorted or as it is. */
+function fileTrees(view: JavaFile, sorted: boolean): string {
+  return JSON.stringify(
+    view.nodes.map((node) => {
+      const tree = node.system.fileSystem as JavaTree | null | undefined;
+      return tree === undefined || tree === null ? null : sorted ? sortedTree(tree) : tree;
+    }),
+  );
+}
+
 function mapSystems(view: JavaFile, system: (node: JavaNode, index: number) => Record<string, unknown>): JavaFile {
   return { ...view, nodes: view.nodes.map((node, index) => ({ ...node, system: system(node, index) })) };
 }
@@ -163,6 +233,9 @@ const departed = {
   documentation: new Set<string>(),
   switchSsid: new Set<string>(),
   modemRoles: new Set<string>(),
+  routerFiles: new Set<string>(),
+  fileTypes: new Set<string>(),
+  fileOrder: new Set<string>(),
 };
 
 describe('the editor model exported, as Java loads it', () => {
@@ -192,10 +265,14 @@ describe('the editor model exported, as Java loads it', () => {
       const source = original[name]!;
       const nodeIds = project.graph.nodes.map((node) => node.id);
       const pairs = nodeIds.map((id) => project.remoteLinkConfigurations.get(id)?.pairIdentifier);
+      // What each router's file adds to its constructor's files.
+      const added = topology.nodes.map((node) => (node.system.templateFiles === true ? (node.system.fileSystem?.children.length ?? 0) : 0));
       const steps: [keyof typeof departed, (view: JavaFile) => JavaFile][] = [
         ['generatedMac', (view) => DEPARTURES.generatedMac(view, macs)],
         ['switchSsid', (view) => DEPARTURES.switchSsid(view, nodeIds)],
         ['modemRoles', (view) => DEPARTURES.modemRoles(view, pairs)],
+        ['routerFiles', (view) => DEPARTURES.routerFiles(view, added)],
+        ['fileTypes', (view) => DEPARTURES.fileTypes(view)],
         ['documentation', (view) => DEPARTURES.documentation(view)],
       ];
       let expected = source;
@@ -208,6 +285,9 @@ describe('the editor model exported, as Java loads it', () => {
         }
         expected = next;
       }
+      if (fileTrees(expected, true) === fileTrees(java!, true) && fileTrees(expected, false) !== fileTrees(java!, false)) {
+        departed.fileOrder.add(name);
+      }
       expect(topologyOf({ ...java!, documentation: sortedDocumentation(java!.documentation) })).toEqual(topologyOf(expected));
     });
   }
@@ -234,12 +314,49 @@ function emptyProject(): ProjectToExport {
     dhcpServerConfigurations: new Map(),
     portForwardingRowsByNodeId: new Map(),
     remoteLinkConfigurations: new Map(),
+    virtualFileSystems: new Map(),
     documentationItems: [],
   };
 }
 
 const port = (id: string) => ({ id, label: id, isOccupied: false });
 
+/** Bytes of a length: (index * 37 + 11) mod 256. */
+function bytesOf(length: number): Uint8Array {
+  return Uint8Array.from({ length }, (_, index) => (index * 37 + 11) % 256);
+}
+
+/**
+ * Nested directories, text with a known extension and without one, a PNG and
+ * a JPEG, binary data with and without a media type, 57 bytes — one line of
+ * Base64 exactly.
+ */
+function syntheticFiles(): VirtualFileSystem {
+  const files = new VirtualFileSystem();
+  files.createDirectory('/docs/deep', true);
+  files.writeTextFile('/docs/readme.txt', 'Zeile 1\r\nZeile 2');
+  files.writeTextFile('/docs/deep/notes', 'no extension');
+  files.writeTextFile('/index.HTML', '<p>upper case extension</p>');
+  files.writeImageFile('/bild.png', bytesOf(57), 'image/png');
+  files.writeImageFile('/foto.jpg', bytesOf(100), 'image/jpeg');
+  files.writeBinaryFile('/daten.bin', bytesOf(58), 'application/zip');
+  files.writeBinaryFile('/roh', bytesOf(3));
+  return files;
+}
+
+/** The files a router's or home router's constructor makes, as Java loaded them from the corpus. */
+function templateOf(javaClass: string): unknown[] {
+  const node = Object.values(original)
+    .flatMap((file) => file.nodes)
+    .find((each) => each.class === javaClass);
+  return (node!.system.fileSystem as JavaTree).children.slice(0, 1);
+}
+
+/** A file as the oracle describes it: its content's UTF-16 length and the SHA-256 of its UTF-8 bytes. */
+function javaFile(name: string, type: string | null, content: string) {
+  return { file: name, type, length: content.length, sha256: createHash('sha256').update(content, 'utf8').digest('hex'), children: [] };
+}
+
 /**
  * What the corpus lacks: a label with IP and MAC, a position between
  * pixels, a switch with five ports, a wireless notebook, a router with three
@@ -319,6 +436,7 @@ const SYNTHETIC: ProjectToExport = {
     ],
   ]),
   portForwardingRowsByNodeId: new Map([['gw', [{ protocolValue: 'TCP', publicPortValue: '8080', lanIPAddress: '192.168.1.10', lanPortValue: '80' }]]]),
+  virtualFileSystems: new Map([['pc', syntheticFiles()]]),
   remoteLinkConfigurations: new Map([
     ['m1', { pairIdentifier: 'java-modem-port-4242', latencyMilliseconds: 20, isEnabled: true }],
     ['m2', { pairIdentifier: 'java-modem-port-4242', latencyMilliseconds: 20, isEnabled: true }],
@@ -390,6 +508,20 @@ describe('a model beyond the corpus, as Java loads it', () => {
             manualRoutes: [['10.5.0.0', '255.255.0.0', '10.0.0.254', '10.0.0.1']],
             dhcpClient: true,
             dhcpServer: JAVA_DHCP_DEFAULTS,
+            fileSystem: sortedTree({
+              directory: 'root',
+              children: [
+                {
+                  directory: 'docs',
+                  children: [{ directory: 'deep', children: [javaFile('notes', 'text', 'no extension')] }, javaFile('readme.txt', 'txt', 'Zeile 1\r\nZeile 2')],
+                },
+                javaFile('bild.png', 'png', javaBase64(bytesOf(57))),
+                javaFile('daten.bin', 'zip', javaBase64(bytesOf(58))),
+                javaFile('foto.jpg', 'jpg', javaBase64(bytesOf(100))),
+                javaFile('index.HTML', 'html', '<p>upper case extension</p>'),
+                javaFile('roh', '', javaBase64(bytesOf(3))),
+              ],
+            }),
           },
         },
         {
@@ -408,7 +540,7 @@ describe('a model beyond the corpus, as Java loads it', () => {
           useIpAsName: false,
           useMacAsName: true,
           ports: [card('10.0.0.2', '255.255.255.0', stableGeneratedMacAddress('n0'), '', '', true)],
-          system: { ssid: 'net', manualRoutes: [], dhcpClient: false, dhcpServer: JAVA_DHCP_DEFAULTS },
+          system: { ssid: 'net', manualRoutes: [], dhcpClient: false, dhcpServer: JAVA_DHCP_DEFAULTS, fileSystem: { directory: 'root', children: [] } },
         },
         {
           class: 'Vermittlungsrechner',
@@ -423,6 +555,7 @@ describe('a model beyond the corpus, as Java loads it', () => {
           ],
           system: {
             ripEnabled: true,
+            fileSystem: sortedTree({ directory: 'root', children: templateOf('Vermittlungsrechner') as JavaTree[] }),
             manualRoutes: [['10.6.0.0', '255.255.0.0', '10.1.0.2', '10.1.0.1']],
             dhcpClient: false,
             dhcpServer: JAVA_DHCP_DEFAULTS,
@@ -452,6 +585,7 @@ describe('a model beyond the corpus, as Java loads it', () => {
             card('192.168.1.1', '255.255.255.0', stableGeneratedMacAddress('g1'), '', ''),
           ],
           system: {
+            fileSystem: sortedTree({ directory: 'root', children: templateOf('Gateway') as JavaTree[] }),
             manualRoutes: [],
             dhcpClient: true,
             dhcpServer: {
@@ -498,6 +632,15 @@ const JAVA_DHCP_DEFAULTS = {
 
 // ── Rules the corpus does not exercise ─────────────────────────────────────
 
+describe('javaBase64', () => {
+  // FILIUS's Base64.encodeBytes around its line length (tools/java-oracle Base64Cases).
+  const cases = JSON.parse(readFileSync(join(here, 'base64.java.json'), 'utf8')) as [number, string][];
+  it.each(cases)('encodes %i bytes as Java does', (length, java) => {
+    const bytes = Uint8Array.from({ length }, (_, index) => (index * 37 + 11) % 256);
+    expect(javaBase64(bytes)).toBe(java);
+  });
+});
+
 describe('exportProject rules', () => {
   const node = (id: string, kind: TopologyNode['kind'], ports: string[], extra: Partial<TopologyNode> = {}): TopologyNode => ({
     id,
diff --git a/packages/fls/test/exported.java.json b/packages/fls/test/exported.java.json
index 37ae5ee..ca1bf7b 100644
--- a/packages/fls/test/exported.java.json
+++ b/packages/fls/test/exported.java.json
@@ -229,7 +229,27 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 538,
+                    "sha256": "1966c377d3651754cfc513da8f425ec0e943e6cc5e8f7112aa06102e21eb0775",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -271,7 +291,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 36,
+                    "sha256": "c4f62d9c112a0def5f67e6b803e8a55886a46712b52bfb73941e12f2f8a63c59",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -728,7 +761,7 @@
         ]
       }
     ],
-    "sha256": "f0defe45fbcc22b7a6ab73d3961907737ac5b528c362855bb236befa83e5507b"
+    "sha256": "de90771cb42c28259bb07b52b5b87fc26e8a084c0a8ee2a34ed515fc372f0b9d"
   },
   "ipad-fixtures/dns_server.fls": {
     "success": true,
@@ -801,7 +834,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 84,
+                    "sha256": "84d02c9a311e5cc7d1c45f3da3f30331903e8f8fc6c45e0d8a2500d393a6adb9",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -843,7 +889,31 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 557,
+                    "sha256": "7d56103add4688141350c5901c1c9bb2c9495a054531b71a32cc9f96aed4ef45",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "www.conf",
+                "children": []
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -927,7 +997,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 47,
+                    "sha256": "d6fcb4528251a65a261ddefad36602c40aa55574cdb88d711a8955d999f2473a",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -1010,7 +1093,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 68,
+                    "sha256": "2f916dbcb3ff8d29840ee37fe341fd8d323960526e0c891128963217d4039e53",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -1052,7 +1148,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 34,
+                    "sha256": "fdba09cf276c8c66cf4676b2c5b741075268911b5ebac2c384c187a6f7137282",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -1190,7 +1299,7 @@
       }
     ],
     "documentation": [],
-    "sha256": "6b40b826ebbd20964e1e4f4c19c3be105d5357704c6966aa875241cabaeec759"
+    "sha256": "c653639f118af6851ce1bbfe90da6d131a69cd0ddbcce942376528c6f8972231"
   },
   "ipad-fixtures/zwei_rechnernetze_komplett.fls": {
     "success": true,
@@ -1304,7 +1413,51 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 33,
+                    "sha256": "3d801783d135a0e42a61ecbba025a318f92c79945e0ca7ae6ea54698b6f5e917",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 557,
+                    "sha256": "156dfa798344ce7f75e3f40ab416c5e2c994c68a110cec5c8d686c31a403f10b",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "www.conf",
+                "children": [
+                  {
+                    "file": "vhosts",
+                    "type": "text",
+                    "length": 52,
+                    "sha256": "528219400a878871604b1ed891f8926fcf142fbaa329722d1b6fcec159c54241",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -1388,7 +1541,39 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 557,
+                    "sha256": "7d56103add4688141350c5901c1c9bb2c9495a054531b71a32cc9f96aed4ef45",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "www.conf",
+                "children": [
+                  {
+                    "file": "vhosts",
+                    "type": "text",
+                    "length": 50,
+                    "sha256": "49583d26538d3b0a66f4332e97ffeaeee1b91c4199dc44deaaa5f1e40ffc6089",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -1567,7 +1752,7 @@
       }
     ],
     "documentation": [],
-    "sha256": "2ed2c7a1240329c741000aa6eec7f8ed721e5448efc957cdc8ab04dd94898f69"
+    "sha256": "fd7a250c308e2ade4b7aed196c145b4d06742394834bbea966d922002ecafb3e"
   },
   "java-examples/Internet_Complete_with_e-Mail_Webserver_Intranet_Portforwarding_Firewall_DHCP_EN.fls": {
     "success": true,
@@ -1599,7 +1784,15 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "file": "konten.txt",
+                "type": "txt",
+                "length": 84,
+                "sha256": "011c91d5e632db92ddd42ddf351d2741a99be3410f76b6528fbeca029ce90ab5",
+                "children": []
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": true,
@@ -1682,7 +1875,15 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "file": "konten.txt",
+                "type": "txt",
+                "length": 88,
+                "sha256": "f4692cfecba61e6a4f0c6db1009cf76756d0a0239b1d2ca4ab5bd95693c3d63f",
+                "children": []
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": true,
@@ -2238,7 +2439,27 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 214,
+                    "sha256": "8c8286bc4ce20a063fd6bcea621c7e576ec1b55b172c3f33d226be0d34cb32a4",
+                    "children": []
+                  },
+                  {
+                    "file": "restored-1770036475063",
+                    "type": "text",
+                    "length": 215,
+                    "sha256": "024f81af0105fc629070ef4c3de21426c0e37cac4a415c1cb3ad01edf726e8ab",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -2280,7 +2501,27 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 500,
+                    "sha256": "94fc9cc5ea871634a045e3e2c01838796d4623ec4488ea23cff50e949c2929b4",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -2322,7 +2563,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "mailserver",
+                "children": [
+                  {
+                    "file": "konten.txt",
+                    "type": "txt",
+                    "length": 90,
+                    "sha256": "378f8265131d36031047d7918f0e5931c746c52bea39758143f7a42ed16cc379",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -2364,7 +2618,20 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "mailserver",
+                "children": [
+                  {
+                    "file": "konten.txt",
+                    "type": "txt",
+                    "length": 46,
+                    "sha256": "d860c7be31f9fa05c689eba6f5b527371e3c81de5e54aa93719a09decd44fb93",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -2406,7 +2673,39 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 33,
+                    "sha256": "5f8235d016bcc8024b554ec91df22ec0bebab7f799fc6009bbd34073224c87d4",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 502,
+                    "sha256": "742fcdde965a05cb80624374067cab0560a9196d224d97d5e7ab9bae6c507127",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -2526,7 +2825,15 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "file": "konten.txt",
+                "type": "txt",
+                "length": 78,
+                "sha256": "37acca898f0c5587824be7fe2ea7ca4771976a2a16b90dc262531126d4970437",
+                "children": []
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": true,
@@ -2568,7 +2875,15 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "file": "konten.txt",
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+                "sha256": "cd35dc5dacfe0681c4ca63b0930d64586328f35313bfd207fe90c9647361de63",
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@@ -3786,7 +4101,7 @@
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+    "sha256": "55c56cb7e5ce455128c180515c6b12a93c2f57256b841521856bb127aa4d5ba0"
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     "success": true,
@@ -3818,7 +4133,15 @@
           "manualRoutes": [],
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-            "children": []
+            "children": [
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+                "sha256": "cd35dc5dacfe0681c4ca63b0930d64586328f35313bfd207fe90c9647361de63",
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@@ -3901,7 +4224,15 @@
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-            "children": []
+            "children": [
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+                "sha256": "584f97b2108104e758f2896f914a8c02f91bedc28dc4d762714596c116c853c5",
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@@ -4457,7 +4788,20 @@
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+            "children": [
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@@ -4499,7 +4843,27 @@
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@@ -4541,7 +4905,20 @@
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+            "children": [
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@@ -4583,7 +4960,20 @@
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+            "children": [
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@@ -4625,7 +5015,39 @@
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+            "children": [
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@@ -4745,7 +5167,15 @@
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+            "children": [
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+                "sha256": "6d8585e1f74b612e758505a156694dfb412b842bdc28e8ed3841199a3970682c",
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@@ -4787,7 +5217,15 @@
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+            "children": [
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@@ -5963,7 +6401,7 @@
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+    "sha256": "9bf1d655d2c53bb7887271c97b65518c03461d2237575ccc855d0660770eadcd"
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@@ -6195,7 +6633,27 @@
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+            "children": [
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@@ -6237,7 +6695,20 @@
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+            "children": [
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@@ -6694,7 +7165,7 @@
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@@ -6921,7 +7392,7 @@
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@@ -7341,7 +7812,7 @@
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@@ -7414,7 +7885,20 @@
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-            "children": []
+            "children": [
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@@ -7456,7 +7940,31 @@
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+            "children": [
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@@ -7540,7 +8048,20 @@
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@@ -7623,7 +8144,20 @@
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@@ -7665,7 +8199,20 @@
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@@ -7803,7 +8350,7 @@
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+    "sha256": "c653639f118af6851ce1bbfe90da6d131a69cd0ddbcce942376528c6f8972231"
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@@ -8003,7 +8550,65 @@
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-            "children": []
+            "children": [
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+                    "sha256": "3f9f9a107b72e97f97671f00232db9ab60e96859d6be66553faf329b64136427",
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@@ -8500,7 +9105,7 @@
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   "java-examples/email_komplett.fls": {
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@@ -8532,7 +9137,27 @@
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-            "children": []
+            "children": [
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@@ -8574,7 +9199,15 @@
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@@ -8616,7 +9249,15 @@
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@@ -8658,7 +9299,15 @@
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@@ -8700,7 +9349,15 @@
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@@ -8783,7 +9440,20 @@
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@@ -8825,7 +9495,20 @@
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+            "children": [
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@@ -8867,7 +9550,20 @@
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+            "children": [
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@@ -9022,7 +9718,7 @@
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@@ -9423,7 +10119,20 @@
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+            "children": [
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@@ -9507,7 +10216,27 @@
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@@ -9591,7 +10320,27 @@
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@@ -9956,7 +10705,7 @@
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@@ -9988,7 +10737,15 @@
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@@ -10030,7 +10787,39 @@
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@@ -10072,7 +10861,15 @@
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@@ -10155,7 +10952,20 @@
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@@ -10197,7 +11007,20 @@
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@@ -10239,7 +11062,20 @@
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@@ -10424,7 +11260,7 @@
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@@ -10593,7 +11453,7 @@
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@@ -10667,7 +11527,19 @@
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@@ -10820,7 +11692,7 @@
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@@ -12336,7 +13301,7 @@
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@@ -12451,7 +13416,27 @@
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@@ -12609,7 +13594,39 @@
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@@ -12861,7 +13878,7 @@
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@@ -12976,7 +13993,27 @@
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@@ -13134,7 +14171,39 @@
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@@ -13259,7 +14328,27 @@
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@@ -13301,7 +14390,20 @@
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@@ -13767,7 +14869,7 @@
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@@ -13799,7 +14901,45 @@
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@@ -13841,7 +14981,15 @@
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@@ -13935,7 +15083,7 @@
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@@ -14049,7 +15197,51 @@
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+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 33,
+                    "sha256": "3d801783d135a0e42a61ecbba025a318f92c79945e0ca7ae6ea54698b6f5e917",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 557,
+                    "sha256": "156dfa798344ce7f75e3f40ab416c5e2c994c68a110cec5c8d686c31a403f10b",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "www.conf",
+                "children": [
+                  {
+                    "file": "vhosts",
+                    "type": "text",
+                    "length": 52,
+                    "sha256": "528219400a878871604b1ed891f8926fcf142fbaa329722d1b6fcec159c54241",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -14133,7 +15325,39 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 557,
+                    "sha256": "7d56103add4688141350c5901c1c9bb2c9495a054531b71a32cc9f96aed4ef45",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "www.conf",
+                "children": [
+                  {
+                    "file": "vhosts",
+                    "type": "text",
+                    "length": 50,
+                    "sha256": "49583d26538d3b0a66f4332e97ffeaeee1b91c4199dc44deaaa5f1e40ffc6089",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -14312,7 +15536,7 @@
       }
     ],
     "documentation": [],
-    "sha256": "2ed2c7a1240329c741000aa6eec7f8ed721e5448efc957cdc8ab04dd94898f69"
+    "sha256": "fd7a250c308e2ade4b7aed196c145b4d06742394834bbea966d922002ecafb3e"
   },
   "java-tests/einfaches_rechnernetz_komplett.fls": {
     "success": true,
@@ -14512,7 +15736,65 @@
           "manualRoutes": [],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "dns",
+                "children": [
+                  {
+                    "file": "hosts",
+                    "type": "text",
+                    "length": 64,
+                    "sha256": "94c7a19c36a5e11af62ffba031840ce9c238231f18f1e999f1a908b3956540aa",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "webserver",
+                "children": [
+                  {
+                    "file": "800px-Loewe_3.JPG",
+                    "type": "jpg",
+                    "length": 117116,
+                    "sha256": "04d6353a6e750e8af80058fc299ebaaf85a14d740eaa7c19b5db8b42e9000f9d",
+                    "children": []
+                  },
+                  {
+                    "file": "index.html",
+                    "type": "html",
+                    "length": 615,
+                    "sha256": "c7682b3a9758588021d73ec7a01769c1a3056b666a252822ecaea18514b6e784",
+                    "children": []
+                  },
+                  {
+                    "file": "meine-seite.html",
+                    "type": "html",
+                    "length": 121,
+                    "sha256": "3f9f9a107b72e97f97671f00232db9ab60e96859d6be66553faf329b64136427",
+                    "children": []
+                  },
+                  {
+                    "file": "splashscreen-mini.png",
+                    "type": "png",
+                    "length": 8397,
+                    "sha256": "c876b828d7258ddfce4aa01ecaa69d4685d238bccf6a94842972165bd1a0107c",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "directory": "www.conf",
+                "children": [
+                  {
+                    "file": "vhosts",
+                    "type": "text",
+                    "length": 52,
+                    "sha256": "528219400a878871604b1ed891f8926fcf142fbaa329722d1b6fcec159c54241",
+                    "children": []
+                  }
+                ]
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": false,
@@ -15009,7 +16291,7 @@
       }
     ],
     "documentation": [],
-    "sha256": "b6c7806c4394e91a338416bb8d9547d9f7f5cba0d77edbcf99d0963b00a9cabe"
+    "sha256": "cdba1260edf112085e1975c8ad76342fbcb59e72bbc3b6bc7efa7bc97235d706"
   },
   "java-tests/empty.fls": {
     "success": true,
@@ -15055,7 +16337,67 @@
           ],
           "fileSystem": {
             "directory": "root",
-            "children": []
+            "children": [
+              {
+                "directory": "docs",
+                "children": [
+                  {
+                    "directory": "deep",
+                    "children": [
+                      {
+                        "file": "notes",
+                        "type": "text",
+                        "length": 12,
+                        "sha256": "5344287ad0cd517b62386e7698af494ea129fbf7fa96a5905ca0011d4b972a40",
+                        "children": []
+                      }
+                    ]
+                  },
+                  {
+                    "file": "readme.txt",
+                    "type": "txt",
+                    "length": 16,
+                    "sha256": "926b191ec3a9aaaf0bf36487aa8b728b2ba8fc93fa27ae3f6ba999f19d6a9ef7",
+                    "children": []
+                  }
+                ]
+              },
+              {
+                "file": "bild.png",
+                "type": "png",
+                "length": 77,
+                "sha256": "57af5eced0df44fdb2e7ab8313ebc1488ca3a9dd995a83f19ea04e05b6e95d8e",
+                "children": []
+              },
+              {
+                "file": "daten.bin",
+                "type": "zip",
+                "length": 81,
+                "sha256": "e28d2a92bdde4fd7a0cc04c4451025dc53250493a4796a1b0bd7b5995f2dd22e",
+                "children": []
+              },
+              {
+                "file": "foto.jpg",
+                "type": "jpg",
+                "length": 137,
+                "sha256": "067cf19657ad73978e20da6cdbdddff3f1815736026938b652cbe553c2ee4ab0",
+                "children": []
+              },
+              {
+                "file": "index.HTML",
+                "type": "html",
+                "length": 27,
+                "sha256": "ac4b4251cfd56976b9eeb547912ff7e709d56bdb1d1caa0ade73dff843dff318",
+                "children": []
+              },
+              {
+                "file": "roh",
+                "type": "",
+                "length": 4,
+                "sha256": "09006ade084f4668397a1e9e1d7763c683af7957e3a62e04e039425aaaeff7aa",
+                "children": []
+              }
+            ]
           },
           "applications": [],
           "dhcpClient": true,
@@ -15506,6 +16848,6 @@
         ]
       }
     ],
-    "sha256": "874f2f33f2f5beb5c301fc58f61deacc666fe65fb7289cd52abae84bd7dfb8d4"
+    "sha256": "16986c17c7720dffb33a07d64a316de8ce9d9fca08bec1f3ebcfe68de8cb0370"
   }
 }
diff --git a/tools/java-oracle/README.md b/tools/java-oracle/README.md
index e700bd2..56cda43 100644
--- a/tools/java-oracle/README.md
+++ b/tools/java-oracle/README.md
@@ -98,6 +98,15 @@ passt. Je Kabel steht auch `panel`: die Geräte, zwischen denen die
 Oberfläche es zeichnet (`JCablePanel.ziel1/ziel2`) — im Korpus bei allen 183
 Kabeln die Geräte, die es verbindet.
 
+## Wie Java Base64 schreibt
+
+`Base64Cases` ruft Filius' eigenes `Base64.encodeBytes` (iHarder 2.x) auf
+Byte-Folgen von 19 Längen rund um die Zeilenlänge auf
+(`packages/fls/test/base64.java.json`). Befund: nach je 76 Zeichen ein
+`\n`, auch nach der letzten vollen Zeile, dann der aufgefüllte Rest ohne
+Umbruch. So stehen Bilder in den Dateien, auch die, die Javas Konstruktoren
+selbst anlegen.
+
 ## Was Java aus unserem XML macht
 
 `BeansDump` liest jede `*.xml` unter `packages/fls/test/beans/` mit
diff --git a/tools/java-oracle/run.sh b/tools/java-oracle/run.sh
index 15fa3cf..874e663 100755
--- a/tools/java-oracle/run.sh
+++ b/tools/java-oracle/run.sh
@@ -21,7 +21,7 @@ if [ ! -f "$upstream/target/filius.jar" ]; then
 fi
 classpath="$upstream/target/filius.jar:$upstream/target/lib/*"
 mkdir -p "$here/.build"
-javac -encoding UTF-8 -d "$here/.build" -cp "$classpath" "$here/src/FlsOracle.java" "$here/src/GetterDefaults.java" "$here/src/IpCheckCases.java" "$here/src/DnsHostsCases.java" "$here/src/EmailFileCases.java" "$here/src/BeansDump.java"
+javac -encoding UTF-8 -d "$here/.build" -cp "$classpath" "$here/src/FlsOracle.java" "$here/src/GetterDefaults.java" "$here/src/IpCheckCases.java" "$here/src/DnsHostsCases.java" "$here/src/EmailFileCases.java" "$here/src/BeansDump.java" "$here/src/Base64Cases.java"
 # FILIUS writes its settings below $HOME; keep them out of the real one.
 mkdir -p "$here/.build/home"
 # Removed first: a crashed run must not leave the previous result standing.
@@ -67,6 +67,12 @@ rm -f "$ipcheck"
 HOME="$here/.build/home" java -cp "$classpath:$here/.build" IpCheckCases "$cases" "$ipcheck" 2>&1 | grep -v 'logback\|^$' || true
 test -s "$ipcheck"
 
+# Base64.encodeBytes around its line length (packages/fls/src/exportProject.ts, javaBase64).
+base64="$root/packages/fls/test/base64.java.json"
+rm -f "$base64"
+HOME="$here/.build/home" java -cp "$classpath:$here/.build" Base64Cases "$base64" 0 1 2 3 55 56 57 58 59 113 114 115 116 171 172 2000 2001 2002 2052 2>&1 | grep -v 'logback\|^$' || true
+test -s "$base64"
+
 # DNSServer's own reading of /dns/hosts on hand-picked files (packages/fls/src/dnsHosts.ts).
 cases="$root/packages/fls/test/dns-hosts.cases.txt"
 dnshosts="$root/packages/fls/test/dns-hosts.java.json"
diff --git a/tools/java-oracle/src/Base64Cases.java b/tools/java-oracle/src/Base64Cases.java
new file mode 100644
index 0000000..ff13e5d
--- /dev/null
+++ b/tools/java-oracle/src/Base64Cases.java
@@ -0,0 +1,32 @@
+// Runs FILIUS's own Base64.encodeBytes on byte arrays of the given lengths
+// and writes what Java returns — the reference for javaBase64 in
+// packages/fls/src/exportProject.ts. The bytes of length n are
+// (index * 37 + 11) mod 256, so both sides make them alike.
+//
+// Usage: java -cp filius.jar:lib/*:classes Base64Cases <output json> <length>...
+
+import filius.rahmenprogramm.Base64;
+
+import java.io.FileOutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Base64Cases {
+
+    public static void main(String[] args) throws Exception {
+        List<Object> result = new ArrayList<>();
+        for (int argument = 1; argument < args.length; argument++) {
+            int length = Integer.parseInt(args[argument]);
+            byte[] bytes = new byte[length];
+            for (int index = 0; index < length; index++) bytes[index] = (byte) ((index * 37 + 11) % 256);
+            result.add(Arrays.asList(length, Base64.encodeBytes(bytes)));
+        }
+        try (FileOutputStream out = new FileOutputStream(args[0])) {
+            out.write((FlsOracle.Json.write(result, "") + "\n").getBytes(StandardCharsets.UTF_8));
+        }
+        System.out.println("base64 cases: " + result.size());
+        System.exit(0);
+    }
+}