This build seems to crash when executing the "firefox media" test cases when media.fragmented-mp4.gmp.enabled=true is enabled in about:config - this is a non-standard setting aimed at allowing MSE & H.264 to work properly.

Notable symptoms with that setting enabled: Youtube videos appear to not play with "An error occurred" - running through the "firefox media" tests actually crashes Firefox.

Issues are not present on a clean profile, due to that setting being false by default.

Test Case firefox addons
Test Case firefox browse

No issues

BZ#1282203 Breeze mouse cursor theme missing after upgrade

Error: nothing provides kf5-filesystem >= 5.15.0 needed by kf5-kdesu-5.15.0-2.fc23.x86_64

Noticed after system-upgrade