Options - Quick source viewer

Show the number of Javascript and CSS nodes as a badge in the toolbar.

Badge

Initially beautifies source code. (Beautify modifies styling such as new lines, whitespace and indentation to make source more readable.)

You can control this on demand in the source view with a button or a keyboard shortcut 'b'.

Beautify

Initially displays line numbers.

You can control this on demand in the source view with a keyboard shortcut 'n'.

Line numbers

Show caching information of external files. Picks the HTTP header "Expires", "Cache-Control" or "Age", in this order.

Cache header

Show onclick handlers with inline javascript.

OnClick

List of source files urls to hilight, one url match per line.

Hilight sources

Adjust the look and feel of the extension with custom CSS. (See the available elements by inspecting the page.)

Custom CSS

by Tomi Mickelsson — tomicloud.com

Credits to jsbeautifier.org and highlight.js