It would be desirable to be able to add a message group to your watchlist (for a given language).
This would allow translators to add e.g. a fundraising banner to their watchlist in order to quickly get a notification if any new/extra translation is needed.
The current mechanism only allows a user to add each individual source message meaning messages added to the group would not trigger a notification.
Watchlist should be triggered either by changes in the message group state for the selected language. I.e. by anything changing the percentage of translated/outdated messages.