Perhaps the post was posted in the wrong place and can be moved or deleted. But it's not entirely clear.
There is a page: https://tildes.net/groups
Where is it written:
Group name colors: subscribed / not subscribed. You can change your subscription status to a group in its sidebar when you are viewing it directly.
I decided to experiment and unsubscribe from some groups. However, there are no changes on this page. Perhaps it’s just me or I’m doing something wrong.