They also removed the ability to preview RSS feeds, which is annoying because one of the few certain ways to subscribe to a feed was to preview it and then hit

They also removed the ability to preview RSS feeds, which is annoying because one of the few certain ways to subscribe to a feed was to preview it and then hit subscribe in whatever addon you were using. In the past it was even possible to subscribe with whatever addon you prefered from the firefox RSS preview directly, but that was already lost after the jump to WebExtensions.