Awesome, thanks for that! By the way: that integration has been co-opted for use by a bunch of overlay software, like gw2taco [1].
So, even if not used for Mumble, it's now a pretty big feature for other 3rd party software. I use it regularly myself.
(For the unfamiliar: gw2taco et al use position/viewport data, I guess, from the GW2 Mumble API to draw an overlay on top of the game with navigational markers/aids.)
Spatial audio support in mumble was just coming around in its early stages when I looked at integrating mumble as a VoIP solution to a Unity3D training simulator project. Good to see it's still around and kicking!
I remember using that in Minecraft with friends. Easy way of finding where your friends are without having to deal with coordinates. That was long ago though so I'm sure there are better built-in ways now.
Didn't personally play with it, but UHC (ultra hardcore, aka PVP with only one live) from a bunch of streamers used it for one season. It was pretty fun to watch: https://youtu.be/WfHtL07nvcE?t=73
Spacial audio really adds a lot to a game. Day of Infamy and Resistance and Liberation are a lot of fun because of it (although RaL is pretty much dead)