We'd like to understand how often each permission is requested by third party origins, and how often that permission is granted. This situation is quite weird from a user perspective and it's not apparent what you grant in all cases. Chrome investigated this: https://docs.google.com/document/d/1iaocsSuVrU11FFzZwy7EnJNOwxhAHMroWSOEERw5hO0/edit https://noncombatant.github.io/permission-delegation-api/#bib-iframe-permissions-chrome And found that it was very rare. We could consider disabling this entirely if we found it was very rare. Even if we don't want to disable it, knowing its occurrence will help us decide what to do in First Party Isolation and Resist Fingerprinting modes.