The Snippets Service hosts small chunks of HTML, CSS, and JavaScript that are displayed on about:home in Firefox, among other places.
You can read more about the Mozilla-hosted instance of Snippets on the wiki.
Snippets is based on Playdoh.
https://abouthome-snippets-service.readthedocs.org/en/latest/
This software is licensed under the
New BSD License. For more
information, read the file LICENSE.