--- a/mobile/android/base/health/BrowserHealthRecorder.java
+++ b/mobile/android/base/health/BrowserHealthRecorder.java
@@ -832,18 +832,22 @@ public class BrowserHealthRecorder imple
      *     ],
      *     "abnormal": [
      *       {"r":"A", "oom": true, "stopped": false}
      *     ]
      *   }
      *
      * "r": reason. Values are "P" (activity paused), "A" (abnormal termination)
      * "d": duration. Value in seconds.
-     * "sg": Gecko startup time. Present if this is a clean launch.
-     * "sj": Java startup time. Present if this is a clean launch.
+     * "sg": Gecko startup time. Present if this is a clean launch. This
+     *       corresponds to the telemetry timer FENNEC_STARTUP_TIME_GECKOREADY.
+     * "sj": Java activity init time. Present if this is a clean launch. This
+     *       corresponds to the telemetry timer FENNEC_STARTUP_TIME_JAVAUI,
+     *       and includes initialization tasks beyond initial
+     *       onWindowFocusChanged.
      *
      * Abnormal terminations will be missing a duration and will feature these keys:
      *
      * "oom": was the session killed by an OOM exception?
      * "stopped": was the session stopped gently?
      */
 
     public static final String MEASUREMENT_NAME_SESSIONS = "org.mozilla.appSessions";