Another user and are currently unsure if something is part of the title or falls under the mentioned guideline (https://musicbrainz.org/doc/Style/Titles#Extra_title_information).
More specifically we are uncertain about these two release groups:
https://musicbrainz.org/release-group/87d0b2cc-6d7f-4c82-9c18-16ca631fc9cc and https://musicbrainz.org/release-group/b7f6bb96-f9d6-4191-a800-60e59536e5d2
Both of these are soundtracks for the game Crypt of the Necrodancer and there is a track for each level.
The problem arises because for both releases there are some sources that add the corresponding level info to the track title, and some that don’t. (For example: Spotify doesn’t add anything to the title (https://open.spotify.com/album/1T8Wx88hZXzn9MQ4LplrB5) while Bandcamp does (https://dbsoundworks.bandcamp.com/album/crypt-of-the-necrodancer-amplified-ost)),
You can also compare the version if you take a look at this edit (https://musicbrainz.org/edit/71198407).
“Shopkeeper” distinguishes different titles, which is why it has to stay, but everything else doesn’t distinguish between titles, which is why we disagree whether they are part of the “real title” or not.
We would be grateful for input on this topic.