After I reset my firefox, all of the hightlights were deleted. I cannot get them back. I made highlights on more than 20 pages. (if someone knows how to get this add-on data back, pls tell me)
Also, always shows "There was an error loading your highlights. Please try refreshing the page" this has never worked on the pop-up interface.
Otherwise, the add-on is handy and user-friendly. If this would be fixed, this would be perfect.

Loosing highlights after page reload :(

On dark mode - text in barely visible :(

Ok, its working. But its pretty useless. There is no catalog where you can search all your hightlight for keywords. There are no labels you can set to find articles in the future again.
And PDFs in the internal viewer are not supported at all.
So you have to search all your bookmarks to refind articles for a keyword or a label again later on.

It looked very promising, but I found out that it's not compatible with Midnight Lizard addon. The highlights are almost invisible and the Color Toggle button don't work.
When I turn-off the Midnight Lizard, highlight something and reload the page, all highlights become lost.