When saving an edit is prevented by the AbuseFilter or SpamBlacklist extensions, the error is currently reported as a successful API response with a 'failure' code in the body ( AbuseFilter: P8988, SpamBlacklist: P8990 ).
In the future, these will be reported as standard API errors (AbuseFilter: P8989, SpamBlacklist: P8991 ).
Clients that do handle AbuseFilter or SpamBlacklist failures specially will need to be updated to check for error codes 'abusefilter-warning', 'abusefilter-disallowed', and/or 'spamblacklist' and handle them as they do the current AbuseFilter and SpamBlacklist failures, if they want to preserve their current special handling.
Note that edit failures due to CAPTCHAs from ConfirmEdit are not being changed at this time. They will continue to be reported as before (ConfirmEdit: P9076 )