We are looking at including metadata in the image in Bug 1798543 - Screenshot Attribution and Annotation. The plan is to add an option to include the URL. That should work for PNG, however different applications surface different subsets of the avail...
We're still actively working on this feature, and collapsing the horizontal tabstrip toolbar when you enable vertical tabs is coming - its just not complete yet.
I can't tell what's going on from the screenshot there. Did you trigger Firefox Screenshots and nothing at all showed up? Or is that the result of taking a screenshot - its captured the web page, but not the video? If you can load about:config and le...
It wasn't working very well. The new implementation fixed dozens of bugs in Screenshots - there's a list of bugs resolved here. The zoom issues described here among them.
