In a chat room room owners can unstar or unpin messages.
However, they can't do that from their chatroom transcript. If they want to cancel stars from way back they are forced to load older messages until they reached the message with the unwanted star.
That is where this script comes handy. It will allow an RO to unstar any message from the transcript.
This script is tested with TamperMonkey and Chrome on Chat.SO and Chat.MSE.
Do note that the star isn't removed when clicking the link. Refresh to see the result.
If you have bug reports or feature request, leave an answer or comment or submit an issue on the GitHub repo.
Post slightly adapted from my answer here