What does the Discogs plugin?

[make-nz]

Is there any docs on what mp3/flac tags would be read/recognised here -- see pic
   

What all my files have is:

• DISCOGS_RELEASE_ID
  

some also have a 2nd tag:

• DISCOGS_ARTIST_ID
  

But they never show up in JF!

Is this by design, like only some JF Metadata plugin would write these?
Or should JF do this without any Metadata downloaders?