Bookmark Player от Etienne

Adds a playlist functionality to Firefox bookmarks.
By clicking on the add-on icon you can choose a bookmark folder to play. The add-on will then
load each link in the tab active at the time of the folder selection. The add-on will wait for the tab to stop playing music before switching to the next link in the folder ten seconds later.
There is no shuffle option.

You can fork it there: https://github.com/EtienneDesticourt/Firefox-Bookmark-Player