Hello!

Some data mined info has revealed a new barbarian kit: the wild magic barbarian. The kit is not from the Player's Handbook, but from a supplement called Tasha's Cauldron of Everything. I don't know much about this kit. I'm guessing it's just a barbarian that can cast wild magic. The BG3 icon is an axe surrounded by a gold flame. There are also animations and VFX unique to this sub-class.

Source: https://techraptor.net/gaming/news/baldurs-gate-3-datamine-reveals-non-phb-material

It's basically a Sharman and imo the marker is there for one of the boss fights not really a playable character... I could be wrong of course but take everything data minned with a grain of salt