This almost works for what I wanted, but then fails in the end.

While nice that everything was sorted as promised the second option mentioned in the addon description was the one that made me install it.
As in, I'm someone with a lot of bookmarks from stuff I am reading it is common to have duplicate bookmarks with only the chapter number differing. I could sort by titles to fix this, but I like the bookmarks sorted by date to know which are the oldest. This addon in theory would allow me to sort by date, and then if two similar bookmarks found they would be paired. But this is not the case. The second sorting option has no effect no matter which option is chosen.