Commit tags should be of general type, prefixed by "ID" and a commit subtype ID. We then have a SubtypeID file in the kernel docs which specifies which subtype it is. A subtype ID should be in the range 0-F. If more than one digit is given, it is an AND operation.
This makes the strings easier to read if you don't care about subtypes and allows an easy way to relate commits of similar subclass.