On the Roon Forum I have come across this interesting post by user woodford:
I was wondering if the Gracenote TLS has had any impact on the development of Songkong and Jaikoz?
Gracenote Three-Line-Solution
No, for starters we have always provided metadata in their own fields rather than try to cram them into existing fields. The original driver for my work has been the MusicBrainz database, it has some flaws but is by far the best database structure.