Fire Source Viewer от Francesco De Stefano

Browser WebExtension for quickly viewing HTML, JavaScript and CSS

Main Features of extension
* Source code with syntax highlighter and beautified for easy reading.
* Icon of add-on in the toolbar shows JavaScript node counts.
* Line numbers, file size and cache header is displayed.
* Copy source code to clipboard.
* Selected urls can be highlighted in the list of source files using options page.

### Limitations
- WebExtension only works on sites that allow content scripts.