I asked this same question recently and didn't even get a reply. Now I know the VRRenderer has bvh export I am going to try it!
Ok, so you need to select BVH in the "video output" box. A bit odd, but yeah. Then it exports the animation instead of video. It goes into saves/vrrenders.
Make sure to set the recording duration to match the length of the animation (default is 10 seconds).
I imported the animation into Blender without issue and it plays and looks fine. Getting that into Unity which doesn't support BVH is proving harder.