https://wiki.musicbrainz.org/Style/Unknown_and_untitled/Special_purpose_track_title#Data_tracks should be updated to be clearer about data tracks now that we're adding support for them. While it's still technically correct, I think the distinction between the data track itself and the content of the data track is quite subtle and it will probably be misleading without further clarification.
If an audio CD contains a data track at the end which is not visible in an audio CD player, it should not be included in the main part of the tracklist.
If the data track contains audio or video tracks, those tracks should be entered in the data tracks section of the tracklist (enabled by selecting the "This disc contains data tracks at the end" option in the release editor).
If an audio CD contains a data track which is visible in an audio CD player (typically as the first track), use [data track] as the track name. If the data track is on a Various Artists release, use [data] as the artist for the track.
I added a distinction between the "main" and "data tracks" parts of the tracklist, which I think clarifies it enough. I also specifically mentioned audio CDs, as this has nothing to do with data CDs, and mentioned that it's the audio and video tracks which we're interested in, to hopefully clarify that it's not intended to be a directory listing of the data track or something.