I found this link: https://bugzilla.mozilla.org/show_bug.cgi?id=1654112
Which contains this comment: https://bugzilla.mozilla.org/show_bug.cgi?id=1654112#c371
Which explains that the improvements came from upgrading their libwebrtc library to version 2H2020. I wasn't able to find release notes for libwebrtc itself.
I found this link: https://bugzilla.mozilla.org/show_bug.cgi?id=1654112
Which contains this comment: https://bugzilla.mozilla.org/show_bug.cgi?id=1654112#c371
Which explains that the improvements came from upgrading their libwebrtc library to version 2H2020. I wasn't able to find release notes for libwebrtc itself.