You are overly paranoid... The GitHub repo is literally the first thing that shows up when searching for "Fedy" on Google:

https://github.com/folkswithhats/fedy

If the "--nogpgcheck" bothers you, a simple text replace over the source code solves it.

Same with the "curl|bash" thing, you are not obligated to run it that way, you can just clone the repo and run it however you want, it is open source!

It is funny the way people overreact with things like this with projects that are open source but are ok installed closed source software and feel safe because they got them from the official repos...