[Milhouse]

Here's a few examples:

Code:

extrajson.songs = file, artist, album, duration
extrajson.movies = trailer, streamdetails, file, mpaa, rating, plot, dateadded, playcount, cast, tag, studio, runtime, country, lastplayed, imdbnumber, votes
extrajson.tvshows.tvshow = plot, rating, cast, file, imdbnumber
extrajson.tvshows.episode = streamdetails, file, dateadded, rating, plot, cast

Any valid field (Kodi JSON RPC API) should work, and the relevant fields will be output on the "Jd" or "J" options (eg. "Jd songs" will include file, artist, album and duration in addition to the basic fields output when using "jd" or "j").