Cruft (occasionally kruft) is computing jargon for "code, data, or software of poor quality".[1] The term may also refer to debris that accumulates on computer equipment. It has been generalized to mean any accumulation of obsolete, redundant, irrelevant, or unnecessary information, especially code.[2]
via en.wikipedia.org
I've been deciphering a software install I didn't do and have definitely found lots of cruft. One problem, though, is I'm not always sure what the cruft is (and so I leave it in).