https://musicbrainz.org/cdstub/KbIrJS.rpLJXt8mhdi3jADaF5i4- has a section called "Disambiguation" which should be called "Comment". https://musicbrainz.org/cdstub/KbIrJS.rpLJXt8mhdi3jADaF5i4-/edit also calls it "disambiguation". CD stubs do not have disambiguation comments (it's all just plain text...). That field is actually just a general comments field for extra information (e.g. in this case, CD Baby IDs).