Genshin Facial Features Via Materials?

Howdy.

I wanted to do a dance sequence with Amber from Genshin impact, the the rig set-up is confusing the heck out of me. It seems like all of her facial features are tied to materials? I don’t see anything on the rig layers to active a facial rig. I also don’t see how to activate the facial material. The character can open and close her mouth based of author pictures so I must be missing something. Is this a usual set-up for anime styled characters?

Thanks in advance.
https://drive.google.com/file/d/143_ivCUO_2ouy7vTdaY7e---OwuMw-Dj/view?usp=sharing

These models use shape eyes for all facial expressions. Can be found by clicking on the face in object mode.