I traced through the code, and this is an artifact resulting from (1) Windows considering a '=' to be a delimiter / space character, so (2) the wildcard routine (called by the fuzzy searches) considers it to be a terminating character (for example, in an executable extension comparison). So it matches directories with no filename; i.e., root directories.
Modifying this would potentially break a lot of things, so since it's not harmful (and since it's worked this way for at least 15 years without issue) I'm inclined to leave it as-is.