diff --git a/.changeset/25921-readerless-presence-sync-helpers.md b/.changeset/25921-readerless-presence-sync-helpers.md
new file mode 100644
index 00000000000..a4afeb74033
--- /dev/null
+++ b/.changeset/25921-readerless-presence-sync-helpers.md
@@ -0,0 +1,11 @@
+---
+'@object-ui/collaboration': patch
+'@object-ui/mobile': patch
+---
+
+refactor(collaboration,mobile): delete the module-local `createPresenceUpdater` and `requestBackgroundSync` helpers that nothing reads
+
+Clause-②: no
+Metadata-protocol: none
+
+Neither name is exported from its package entry (the single `.` export), so no host can import them; the compiled `usePresence.js` and `serviceWorkerSource.js` simply stop carrying the two dead function bodies. Behaviour of every exported name is unchanged.
diff --git a/ui/packages/collaboration/src/usePresence.ts b/ui/packages/collaboration/src/usePresence.ts
index c184b3d9276..d1d0d1a3ea2 100644
--- a/ui/packages/collaboration/src/usePresence.ts
+++ b/ui/packages/collaboration/src/usePresence.ts
@@ -205,41 +205,3 @@ export function usePresence(
     currentUser,
   };
 }
-
-/**
- * Update remote user presence. Call this when receiving presence data
- * from other users via the realtime channel.
- *
- * @returns A function to update or remove a remote user from the presence set.
- */
-export function createPresenceUpdater(): {
-  updateUser: (user: PresenceUser) => void;
-  removeUser: (userId: string) => void;
-  getUsers: () => PresenceUser[];
-  onUsersChange: (callback: (users: Map<string, PresenceUser>) => void) => () => void;
-} {
-  const users = new Map<string, PresenceUser>();
-  const listeners = new Set<(users: Map<string, PresenceUser>) => void>();
-
-  const notify = () => {
-    listeners.forEach(cb => cb(new Map(users)));
-  };
-
-  return {
-    updateUser(user: PresenceUser) {
-      users.set(user.userId, user);
-      notify();
-    },
-    removeUser(userId: string) {
-      users.delete(userId);
-      notify();
-    },
-    getUsers() {
-      return Array.from(users.values());
-    },
-    onUsersChange(callback: (users: Map<string, PresenceUser>) => void) {
-      listeners.add(callback);
-      return () => { listeners.delete(callback); };
-    },
-  };
-}
diff --git a/ui/packages/mobile/src/serviceWorkerSource.ts b/ui/packages/mobile/src/serviceWorkerSource.ts
index dd12fdb58ea..18a3cbe5320 100644
--- a/ui/packages/mobile/src/serviceWorkerSource.ts
+++ b/ui/packages/mobile/src/serviceWorkerSource.ts
@@ -95,15 +95,3 @@ self.addEventListener('sync', (event) => {
 });
 `;
 }
-
-/**
- * Request a one-shot background sync. The page should call this after
- * enqueuing offline work so the browser will wake the SW when the
- * connection returns. Returns false if Background Sync is unsupported.
- */
-export async function requestBackgroundSync(tag = 'objectui-offline-queue'): Promise<boolean> {
-  if (typeof navigator === 'undefined') return false;
-  const reg: any = await (navigator as any).serviceWorker?.ready;
-  if (!reg || !reg.sync) return false;
-  try { await reg.sync.register(tag); return true; } catch { return false; }
-}