Thanks for the thorough analysis! Very insightful. So the 8+3 structure still simplifies matching: To my recollection at least, in DOS a * would always wildcard out the rest of the filename component (I did not look in the code), so things like FOOxBAR.TXT weren't possible. That way though, the common x.TXT still is.

Read "x" as *, because I could not for the life of me get the star work as a star within a word in this comment.