At this point, Firefox takes a break and checks for available updates. It doesn't find any, so we get an XML response with an empty <updates> object.
The 2nd addon is WideVine. This is requested directly from Google's gvt1.com domain. Hello again, Google.
I would like to see them proxy calls to Google endpoints, and avoid the initial mozilla.org tab.
If you enjoyed this thread, see the others I did on Opera, Vivaldi, Brave, Dissenter, and Chrome.