What does the "notify" button in AUR do? There are three buttons when looking at a package in AUR: "Vote", "Notify" and "Flag Out-of-date". What does the "Notify" button do?

If you click the notify button, you will get email notifications about new comments in this specific package.

Afterwards you are able to click the same button again to unsubscribe from these notifications if you don't want to get new notifications anymore.