This is a prototype for a product to create better ways of sharing and saving content, starting with screenshots. (This project used to include general page freezing; this functionality has been forked off into pagearchive.)
It is made up of both an add-on (using WebExtensions) and a website using Node.js. The add-on is in
addon/webextension/, and the website is in
Ian has been blogging about the design, definition, and development process.
You can find more information about Page Shot at the Mozilla Wiki page: https://wiki.mozilla.org/Firefox/Page_Shot