506 is a hidden filter on enwiki, which means I (not a sysop or EFM) cannot see https://en.wikipedia.org/wiki/Special:AbuseFilter/506. However, I can still see https://en.wikipedia.org/w/api.php?action=query&list=abuselog&aflfilter=506, which is basically the same content.
I'm marking this as major since it's another data leak.
Version: unspecified
Severity: major