Toggle CSS outline автор theodejager

This extension adds a browser button that toggles a red outline on/off around all elements on a page. Useful for CSS development, to see all the borders of all elements in one glance quickly without opening the developer tools panel. Basically it sets the following style on / off:

* { outline: 1px solid red; }

Source code: https://github.com/theodejager/toggle-css-outline