Yes, those are the messages.
Note that this might not be the AbuseFilter's fault: the names of the actions don't seem to be translated anywhere in MediaWiki, only their descriptions are.
Look for instance at [[Special:ListGroupRights]] or even [[m:Special:GlobalGroupPermissions/steward]]. The difference is that they're usually alongside the translated description, but this may or not be fixable.

It's a bit like the URL parameters (for action= and also log action in Special:Log or group name in Special:ListUsers etc.), which can't be changed.

(In reply to comment #1)

Yes, those are the messages.
Note that this might not be the AbuseFilter's fault: the names of the actions
don't seem to be translated anywhere in MediaWiki, only their descriptions are.
Look for instance at [[Special:ListGroupRights]] or even
[[m:Special:GlobalGroupPermissions/steward]]. The difference is that they're
usually alongside the translated description, but this may or not be fixable.

It's a bit like the URL parameters (for action= and also log action in
Special:Log or group name in Special:ListUsers etc.), which can't be changed.

Even if it isn't the abusefilter's fault and the action names come from mediawiki, maybe it can wrap them in a translation function before showing? (if its not possible for them to be translated in mediawiki itself)

I'm not convinced. Those actions are the values that the "action" variable may take. Localizing them in filter syntax isn't feasible (new translation requires an update of all filters using the old one), so we'd have a non-localized name inside filters and a localised one in logs. My concern is that we would introduce a discrepancy which may cause some confusion. Anyway,the change itself wouldn't be hard, if we decide to go on.