More or less the former; they use a fork of Waydroid called Andromeda (one of the developers used to work on Droidian, I believe); repo.'s at https://github.com/FuriLabs/andromeda. So, you know, it works very similarly but it's not technically the same thing.

It's not particularly easy to find (technically, you can get to it from their website but I think the lack of Google bothering to list it in search results makes most people miss it; I definitely did until it was mentioned in the Telegram/Matrix chat) but they do have an FAQ page that has a lot of details. It's not always as detailed as one might want (so feel free to ask me anything as I'm running the device from day-to-day) but it does have quite a bit; here's their section regarding running Android app.s: https://furilabs.com/faq/#faq-240