Here's a copy of a mail I just sent to stewards-l about the trial deployment of global AbuseFilters:
Hello,
after a long time we're finally confident that the AbuseFilter extension is in a state in which it can be used for global filters. Therefore I'm happy to announce that from now on global AbuseFilters can be used on (some) Wikimedia Wikis.
The filters can be created and edited by Stewards using the normal AbuseFilter interface on meta ( https://meta.wikimedia.org/wiki/Special:AbuseFilter ) and basically work like local filters (you only have to set the "Global filter" flag). Although global AbuseFilters are already in use on Wikimedia Labs for quite some time we would like you to start using them slowly, preferable with logging-only filters to prevent unforeseeable damage.
Global filters are yet enabled on: metawiki, testwiki, test2wiki, mediawikiwiki (They will only filter changes on these wikis... Of course this trial will later be extended to further Wikis and it's planned to cover all Wikis at some point)
Please notice that it's not yet possible to create custom warning message for global filters ( https://bugzilla.wikimedia.org/show_bug.cgi?id=45164 ) and that global filters can't yet be enabled/ disabled for certain wikis only ( https://bugzilla.wikimedia.org/show_bug.cgi?id=41172 ).
Cheers,
Marius Hoch (Hoo man)