You can find it here: Holo Video Chat

Holo Video Chat contains a port of the WebRTC Video Chat plugin for UWP x86, x64 and ARM 32 for the HoloLens 2. It includes the same ICall, IMediaNetwork and IVideoInput C# interfaces that are available for the other platforms.

Holo Video Chat is compatible to WebRTC Video Chat on a network level and it can be used to connect the HoloLens 2 to all other platforms including browser based apps developed on top of awrtc_browser.

For more information check out the Holo Video Chat guide!