They mention SWICG’s data portability spec, I assume they’re referring to LOLA: https://swicg.github.io/activitypub-data-portability/lola

Just lemmy.org.uk for me.

Hexbear is basically only blocks lemmy.world

Hexbear runs an allowlist, they only federate with instances they select.

The secure chat option is something called Matrix, which is a separate service that doesn’t integrate like Reddit’s chat. Lemmy just supports being able to set a Matrix account as the place to reach a user.