Read what the camera follows through one Core module

src/data/followed.js answers what the camera follows: the camera port's
target, or the entity a layer still tracks itself, seen through the same
fields. Ownership checks, render holds, guards, voice actions, the CCTV
pacing and the navigation release paths read it instead of Cesium's
trackedEntity, so they keep working when layers follow through the port.
The release paths stop following, cancel the flight and release the
camera through the port. The rotate refusal names the followed target by
its name or label title.

src/cameraVerbs.js

@@ -18,6 +18,7 @@
  * globe motion, opposite to the camera's travel around Earth.
  */
 
+import { followedOf, isFollowing, onFollowChanged } from './data/followed.js';
 import * as Cesium from 'cesium';
 import { GLOBE_VIEW } from './locations.js';
 import {
@@ -1041,7 +1042,7 @@ export function interruptCameraMotion(reason = 'interrupt') {
   // While an entity is TRACKED, the follow camera owns the reference frame —
   // resetting the lookAt transform here flings the camera into space (field
   // finding). Leave the transform to the tracker; it re-asserts every frame.
-  const tracking = Boolean(_viewer?.trackedEntity);
+  const tracking = isFollowing(_viewer);
   const wasRoute = wasActive && _active.kind === 'route';
   if (
     wasActive &&
@@ -1190,7 +1191,7 @@ function onTick() {
         // only describes Cesium's rotation while the frame is identity.
         if (
           _viewer.scene.mode !== Cesium.SceneMode.SCENE3D ||
-          _viewer.trackedEntity ||
+          isFollowing(_viewer) ||
           _isCockpitActive?.() ||
           !Cesium.Matrix4.equals(cam.transform, Cesium.Matrix4.IDENTITY)
         ) {
@@ -1413,8 +1414,8 @@ export function initCameraVerbs(
   if (_trackingRemover) _trackingRemover();
   // Cockpit can acquire then clear tracking before the next clock tick.
   // Yield on acquisition itself without changing legacy camera motions.
-  _trackingRemover = viewer.trackedEntityChanged?.addEventListener((entity) => {
-    if (entity && _active?.kind === 'rotate_globe')
+  _trackingRemover = onFollowChanged(viewer, (followed) => {
+    if (followed && _active?.kind === 'rotate_globe')
       interruptCameraMotion('globe-camera-owner-changed');
   });
   for (const rm of _inputRemovers) rm();
@@ -1522,15 +1523,14 @@ export function moveCamera(args = {}, runNavigation = null) {
   if (
     (motion === 'rotate_globe' ||
       (motion === 'orbit' && typeof runNavigation !== 'function')) &&
-    _viewer?.trackedEntity
+    isFollowing(_viewer)
   ) {
     // The follow camera owns a tracked view; a lookAt orbit fights it frame
     // by frame and stop rips the camera out (field finding). Honest refusal
     // until tracked-orbit rides the follow camera natively (roadmap).
+    const followed = followedOf(_viewer);
     const label =
-      _viewer.trackedEntity?.name ||
-      _viewer.trackedEntity?.id ||
-      'the tracked target';
+      followed?.name || followed?.labelModel?.title || 'the tracked target';
     return {
       ok: false,
       action: 'move_camera',
@@ -1701,7 +1701,7 @@ export function moveCamera(args = {}, runNavigation = null) {
   const preserveCameraFlight =
     motion === 'orbit' &&
     _viewer.scene.tweens.length > 0 &&
-    !_viewer.trackedEntity;
+    !isFollowing(_viewer);
   return typeof runNavigation === 'function'
     ? runNavigation(start, { preserveCameraFlight })
     : start();