We are adding three functionality changes to Fenced Frames: 1. Enable leaving ad interest groups from urn iFrames and ad component frames Currently calling navigator.leaveAdInterestGroup() without any argument only works in fenced frames. This change enables this API for supporting navigator.leaveAdInterestGroup() without any argument: a) in urn iframes and b) in ad component frames. 2. Introduce reserved.top_navigation_start/commit Fenced frames or URN iframes, when loaded through an API like Protected Audience or Shared Storage, can send out reporting beacons automatically if some event occurs. With this change, we are adding support for top-level navigation start events, in addition to the existing top-level navigation commit events.