Calckey has been one of the more popular Fediverse apps for a while now, and just of today they did a major rebranding.
Firefish’s official account is now live at @firefish. Official announcement post from 4 hours ago.
Currently infosec.town has fully migrated over to Firebird 1.0.0; calckey.social is still in the process of migrating.
As of this thread, the most up-to-date version is hosted on the Codeberg repository. A new docker will be supported at https://hub.docker.com/u/thatonecalculator/firebird once Kainoa finishes sorting out everything (hopefully).
Calckey is a Misskey (https://misskey.io/) fork, hence the name. Misskey is an extremely popular fediverse microblogging service from Japan with a lot of functionalities that Mastodon doesn’t have (quote toot, emoji react, …), in fact if you follow any Japanese accounts on Mastodon there is a good chance they are using Misskey instead
Basically Calckey diverged enough from Misskey (and I suspect Kainoa didn’t like the name) that they agreed to rebrand. Kind of a big deal tbh