This add-on does not properly deinstall. It changes the names of your bookmarks forever.
And after deinstallation it continues to give folder path, domain name and url path when you execute a search.
P.S.
The developer questions my observation about the bookmarks.
I give an example: https://twitter.com/twitter was named in my bookmarks: Twitter. After installation and deinstallation of Filter AwesomeBar it is now named: Twitter ::: ::: dtwitter dcom ::: ptwitterundefined.
Another example: http://www.nytimes.com/ was named in my bookmarks: New York Times. After installation/deinstallation is is now named: New York Times ::: fbookmarksmenu f.media fonlinenz ::: dwww dnytimes dcom ::: undefined. Notice that my folder structure is represented in the new bookmark name.
I use Windows 10 and the newest Firefox 58.0.2 (64-bit). I have tested the add-on in two profiles, to be sure. I have several thousand bookmarks and they are all renamed. Luckily I make frequently back-ups, or I would be very sad.
Maybe I do not fully understand what the developer means with "If you install it and then toggle the Browser action, it will revert your bookmarks to the old values." But I am pretty sure I do not get my old bookmarks back. And also, the search action is permanently changed, as described above.
I feel sorry for the developer. I have no reason to doubt his good intensions.