While alternative app stores operate independently and are required by EU law, Apple is still in a position to exert some control. This became apparent a few weeks ago, when iTorrent users suddenly ran into trouble when installing the app.
Thought this was an interesting story, since it’s pretty analagous to the recent Android situation, with third party app stores being enabled to some extent, but the company retaining ultimate censorship power.
i’m pretty sure you also need to have a mac device since it requires xcode (or did last time i researched it; i don’t have ios anymore)