kosmos.social is one of the many independent Mastodon servers you can use to participate in the fediverse.
kosmos.social is run by the Kosmos open-source co-operative, and is open for new members via invitation by existing ones.

Server stats:

23
active users

Râu Cao ⚡

... The difference being that AppCache is an actual recommendation and widely supported. I'm not saying don't write PWAs using SW, but writing it *today* will almost certainly require changes before 2067. Also just because of other relevant features and browser security changes.