Local (private) full text search of the web pages you've visited. I've pondered making something like this for a long time. Frankly it's something that Mozilla should be making instead of drowning itself in slop. Keeping track of stuff has become very difficult and the current tools, History and Bookmarks, haven't changed in a decade. (This is not a recommendation. I haven't kicked the tires yet, but seems neat to me (tm)) https://hister.org/