Honestly, I don’t really know how many first-party engines Ubisoft currently maintains anymore. Anvil is one of their more popular ones, which was used in Assassin’s Creed, Steep, For Honor, and Tom Clancy’s Ghost Recon Wildlands. Far Cry 5 will be using the Dunia Engine, which was forked from the original CryEngine. Tom Clancy’s The Division, Mario + Rabbids, and the new South Park use Snowdrop. I know that I’m missing some.
Add another one to the list: Voyager, which will be used in Beyond Good and Evil 2.
From what I gather with the video, this engine is optimized for massive differences in scale. The Creative Director for Beyond Good and Evil 2, Michael Ancel, showed the camera (in developer mode) smoothly transition from a high-detailed player model out to a part of a solar system. They claim that the sunset effects are actually caused by the planet’s rotation. Interesting stuff!