Debugger shortcut extension
If you've ever found yourself in need to inspect some elusive piece of markup, especially inside of an iframe, you may find this extension useful.
First you save the shortcut.
Then open devtools, press your shortcut and voila. Extension catches keypresses from inside of iframes as well.
Screenshot shows djangoCMS modal window (contents are an iframe) that has ckeditor (iframe) with open panel (also an iframe). It was a pretty big problem to inspect that markup. Not anymore.
