[silver-xr] Minutes of XR subgroup of 3 December 2020

Summary:

We discussed the scope statement for the XR subgroup work.  We took the 
Scope statement of the strategy paper 
<https://docs.google.com/document/d/1om7h7HE-9sIPeBRmJrBSESQWsMGH8PysiWCpAUWXBUQ/edit#heading=h.r0ra5vhj4cbf> 
and added information to narrow the scope.  We discussed what we would 
be working on next.

Minutes:

https://www.w3.org/2020/12/03-silver-xr-minutes.html