Earlier [I was convinced](https://github.com/matrix-org/synapse/issues/9565) that we didn't have an Admin API for listing media uploaded by a user. Foolishly I was looking under the Media Admin API documentation, instead of the User Admin API documentation.
I thought it'd be helpful to link to the latter so others don't hit the same dead end :)
Protecting media stops it from being quarantined when
e.g. all media in a room is quarantined. This is useful
for sticker packs and other media that is uploaded by
server administrators, but used by many people.
Andrew Morgan