Occasionally a misconfiguration results in edits being seen by MediaWiki as coming from 127.0.0.1, as shown by this non-empty contributions log. Further, wikis such as the English Wikipedia had previously blocked Toolserver IPs but have been unable to do the same for Tool Labs thanks to issues such as T66530.
Since the IPs subject to these issues are well-known and typically don't change, we can easily enough add a configuration option to MediaWiki to treat these IPs as blocked "anon. only, talk page access disabled" without running into the XFF issues described in T66530.