There are a number of orphan action types not belonging to any built-in role:
handshake, mapReduceShardedFinishe, replSetElect, replSetFresh, replSetGetRBID, replSetHearbeat, replSetUpdatePosition, setShardVersion, unsetSharding, _migrateClone,
_recvChunkAbort, _recvChunkCommit, _recvChunkStart, _recvChunkStatus,
_transferMods

SInce there is use case where it makes sense to assign one or a few or these roles to an external user, and the internal user is using them all, areate a new action type "internal" and consolidate all the above ones that are considered internal into the new action type.

Any action types above not considered internal should be matched into an appropriate built-in role.