The linked page is on signalusers.org, but Signal's regular home site is https://signal.org/.
I'm looking all over signal.org for some link from there to signalusers.org, as that would make me more relaxed about the authenticity of the latter -- i.e., that it really is run by the same people who run signal.org.
Yes, maybe I'm being paranoid. But we're talking about an app whose whole purpose is secure communications :-).
https://github.com/signalapp/Signal-Android#contributing-cod...
>For larger changes and feature ideas, we ask that you propose it on the [unofficial Community Forum](https://community.signalusers.org/) for a high-level discussion with the wider community before implementation.
So it’s almost certainly legit, but they really should be linking to signal.org proper for sign-up instructions.
Proper signup instructions probably also shouldn't point to the staging environment :) So the real signup instructions are still on signal.org.
That's a valid concern! At the bottom of signal.org, under "Help", Community" links to signalusers.org