Update: Okay, I finally found this tool in Firefox. Let’s say it did something. I'm not sure exactly what it was, other than opening several tabs quickly and then closing all at once. In the end, I was hoping this would restore icons from my huge backlog of bookmarks but as the description says: "...This extension is ONLY meant to simplify the process of opening every tab, so Firefox can load the fav icon - it does NOTHING else besides this..." Sad to say the tool loaded pages without any favourite icons appearing except for those I already had visited. Would be more of a great tool if it could also check missing or broken bookmark links and icons as well.