I’ve just published an update to my OPML Support Firefox extension for the first time in three years. The extension previously added an OPML button to the toolbar in the Bookmarks Manager, but as of Firefox 20, the button disappears because of a change to the way that the Bookmarks Manager’s toolbar is assembled. Version 3 of OPML Support moves the Import OPML and Export OPML options into the existing Backup/Import button’s menu.

Thanks to the OPML Support users who alerted me to the problem via email and in the comments here, since I don’t often have occasion to check whether my buttons are disappearing.