It says "F-Droid, Aurora Store, and other sources'" so I'm guessing there's no Play store and probably no GMS and other increasingly mandatory proprietary dependencies. Open source Android is in rough shape as a result of Google's tightening the ratchet.

Edit: In a different comment one of the devs clarified that it does have microG, so quite a few apps will actually work.[1]

[1]: https://news.ycombinator.com/item?id=41840021