It seems odd that a single Deep Space Nine track is realeased years after the show ended.
Well, years ago there was no iTunes - and one-off singles like this had little commercial value. But, as a cheap download, McCarthy can share lots of bizarre stuff. He's also done a single interpretation of John Barry's "Somewhere in Time" theme! And two themes from "ST Generations", "The Nexus" and "Closing Titles".
Other recent iTunes additions, by others, include a new version of "Ilia's Theme", two versions of the flute tune from "The Inner Light" (one by McCarthy) and a new version of the opening theme of TAS.
Googling it brings up: http://www.buysoundtrax.com/S_soundtracks.html