--- a/browser/components/BrowserGlue.jsm
+++ b/browser/components/BrowserGlue.jsm
@@ -2244,17 +2244,17 @@ BrowserGlue.prototype = {
     this._scheduleStartupIdleTasks();
     this._lateTasksIdleObserver = (idleService, topic, data) => {
       if (topic == "idle") {
         idleService.removeIdleObserver(
           this._lateTasksIdleObserver,
           LATE_TASKS_IDLE_TIME_SEC
         );
         delete this._lateTasksIdleObserver;
-        this._scheduleArbitrarilyLateIdleTasks();
+        this._scheduleBestEffortUserIdleTasks();
       }
     };
     this._userIdleService.addIdleObserver(
       this._lateTasksIdleObserver,
       LATE_TASKS_IDLE_TIME_SEC
     );
 
     this._monitorScreenshotsPref();
@@ -2281,18 +2281,19 @@ BrowserGlue.prototype = {
    *
    * The functions scheduled here will fire from idle callbacks
    * once every window has finished being restored by session
    * restore, and it's guaranteed that they will run before
    * the equivalent per-window idle tasks
    * (from _schedulePerWindowIdleTasks in browser.js).
    *
    * If you have something that can wait even further than the
-   * per-window initialization, please schedule them using
-   * _scheduleArbitrarilyLateIdleTasks.
+   * per-window initialization, and is okay with not being run in some
+   * sessions, please schedule them using
+   * _scheduleBestEffortUserIdleTasks.
    * Don't be fooled by thinking that the use of the timeout parameter
    * will delay your function: it will just ensure that it potentially
    * happens _earlier_ than expected (when the timeout limit has been reached),
    * but it will not make it happen later (and out of order) compared
    * to the other ones scheduled together.
    */
   _scheduleStartupIdleTasks() {
     const idleTasks = [
@@ -2540,27 +2541,29 @@ BrowserGlue.prototype = {
           }
         },
         task.timeout ? { timeout: task.timeout } : undefined
       );
     }
   },
 
   /**
-   * Use this function as an entry point to schedule tasks that need
-   * to run once per session, at any arbitrary point in time.
+   * Use this function as an entry point to schedule tasks that we hope
+   * to run once per session, at any arbitrary point in time, and which we
+   * are okay with sometimes not running at all.
+   *
    * This function will be called from an idle observer. Check the value of
    * LATE_TASKS_IDLE_TIME_SEC to see the current value for this idle
    * observer.
    *
    * Note: this function may never be called if the user is never idle for the
-   * full length of the period of time specified. But given a reasonably low
-   * value, this is unlikely.
+   * requisite time (LATE_TASKS_IDLE_TIME_SEC). Be certain before adding
+   * something here that it's okay that it never be run.
    */
-  _scheduleArbitrarilyLateIdleTasks() {
+  _scheduleBestEffortUserIdleTasks() {
     const idleTasks = [
       () => {
         this._sendMediaTelemetry();
       },
 
       () => {
         // Telemetry for master-password - we do this after a delay as it
         // can cause IO if NSS/PSM has not already initialized.