A Mastodon host run by a organization that (mostly) fights for privacy and against the browser monopoly.
Right now, it seems they're doing invite only so they can moderately control the load and keep track so everything keeps running.
I didn't get invite code beforehand I just signed in my Firefox account and it allowed me to register, maybe the sign up page message needs to be updated
Unfortunately not. After signing in with my FF account the only thing is see is ‘use an invite code’ or ‘join the waitlist’.