In EDM, and possibly other music genres as well, bootleg is a term used for a remix of a song in which the producer made the remix using only the original song in its finished condition. This differs from a traditional remix in that in a remix (not a bootleg), the producer has access to the individual tracks (vocal, bass, melody, etc.) that make up the original song and uses them to create the remix.
一直忘了回复@失足的怪蜀黍OO

sorry