[alexiaya]

This is nice, but I'm confused about one thing: how can instance owners ensure illegal content such as CSAM doesn't get cached on their servers if defederation is not a thing?

[shkkmo]

My understanding is that a PDS instance only hosts data for it's users.

Caching can happen at Relays or AppViews and those will presumably need to do something to avoid caching CSAM.