I found this add-on when I was looking for a replacement for the "Show Parent Folder" add-on (which was removed/no longer works). I'm glad I gave "Bookmarks Manager..." a try despite the negative reviews, because it works extremely well as a replacement for "Show Parent Folder" (I'm running Firefox Quantum 58.0.02).

Granted, "Bookmarks Manager..." isn't 100% perfect yet -- it's a tad slow if your bookmarks collection is very large, and there are a few bugs that need to be ironed out (window resizing isn't working properly, and the add-on doesn't work if placed inside the "More Tools..." drawer), but the core functionality is there: if you search for a bookmark, this add-on will show its location inside your bookmark tree!