Favicons are stored in the places.sqlite file along with the bookmarks. No, you can't drag a Favicon into your bookmarks. If you would drag the favicon from a tab, all that would happen is that you would be adding the bookmark again and the favicon may not be stored if it wasn't the first time you saved the first time. Try it and see what happens ... There is no field for Favicon on the bookmark contextual menu. There used to be a couple of extensions available at different times that allowed users to add a favicon to a bookmark, but it has been awhile since we've seen that type of extension which was compatible. https://addons.mozilla.org/en-US/firefox/addon/favicon-picker-3/ https://addons.mozilla.org/en-US/firefox/addon/favicon-picker-2/ Neither were updated after a Firefox update broke each one at different times, and no one has updated "3" the last one that got broken.