Fatal error: Cannot declare class Wikimedia\MWConfig\XWikimediaDebug, because the name is already in use
#0 /srv/mediawiki/wmf-config/profiler.php(12): require_once() #1 /srv/mediawiki/wmf-config/PhpAutoPrepend.php(24): require_once()
Notes
A spike of over 7000 fatals in the span of one hour, on the mw1379 server.
It lasted approximately from 2020-06-01 14:00 to 14:50 UTC.
From Logstash mediawiki-errors:
Impact
All web requests on this server were presumably aborted with a system error. Regardless of wiki, user, title, or action.