https://integration.wikimedia.org/ci/job/mwext-Mantle-qunit/51/console
https://integration.wikimedia.org/ci/job/mwext-Mantle-qunit-mobile/49/console
Problem is in MobileFrontend: https://gerrit.wikimedia.org/r/#/c/129335/12/MobileFrontend.php,cm
Version: unspecified
Severity: critical