-tracks may be specified by name or by ID. If you use the name and a track
-appears twice in the queue it is undefined which is affected.
-.SH PREFERENCES
-Currently the following preferences are supported. Some are expected
-to be set by users, others updated automatically by plugins.
-.TP
-.B pick_at_random
-If this preference is present and set to "0" then the track will not
-be picked for random play. Otherwise it may be.
-.TP
-.B played
-A decimal integer giving the number times the track was played. This
-includes tracks that are scratched or were picked at random.
-.TP
-.B played_time
-The last time the track was played, as a \fBtime_t\fR converted to a
-decimal integer.
-.TP
-.B scratched
-The number of times the track has been scratched.
-.TP
-.B requested
-A decimal integer giving the number of times the track was requested.
-(Tracks that are removed before being played are not counted.)
-.TP
-.B tags
-Tags that apply to this track, separated by commas. Tags can contain any
-printing character except comma. Leading and trailing spaces are not
-significant but internal spaces are.
-.IP
-Using the
-.B required-tags
-and
-.B prohibited-tags
-global preferences, it is possible to limit the tracks that will be selected at
-random.
-.TP
-.B trackname_\fICONTEXT\fB_\fIPART\fR
-These preferences can be used to override the filename parsing rules
-to find a track name part. For backwards compatibility,
-\fBtrackname_\fIPART\fR will be used if the full version
-is not present.
-.TP
-.B unscratched
-The number of times the track has been played to completion without
-being scratched.