Which web browser do you use?
I have a Chrome based one, so run scripts with Violent Monkey. You get that here:
Then get the “Set Recording Comments for a Release” script from: GitHub - murdos/musicbrainz-userscripts: Collection of userscripts for MusicBrainz, by various authors Click on INSTALL
Click on Confirm Installation
Now when you go to the tracklist page there is a magic button at the top
Click it and this happens
What you type in the top box sets all the comments to the same.
Also note each track has its own box where you can adjust separate comments.
BONUS POINTS - you want to be able to see this… So install INLINE STUFF
Get this script: konami-command/mb_INLINE-STUFF.user.js at master · jesus2099/konami-command · GitHub
This time you have to click the RAW button
But install in the same way
And now you will see the grey text of the comments that have been added to each Recording
The INLINE STUFF script will add all kinds of extra tweaks to the page. Makes the MB pages more enhanced and detailed.