I'm listening to Charles Mingus' 1959 album Mingus Ah Um on Amazon Music. The titles of the majority of the track on this album are listed with "[Clean]" after the title:
What does "[Clean]" mean in this context? I would normally have thought that this refers to an alternate version with non-explicit (censored) lyrics, but the entire album is instrumental jazz with no lyrics on any track.
If it helps anyone figure it out, I have determined that this version of the album is a later re-issue of the album with expanded uncut versions of several of the tracks as well as three tracks that were not on the original release. However, the list of expanded tracks do not coincide with the tracks that have the "[Clean]" notation.