This extension is a moz: protocol handler for moz://a URLs. After installing it, try going to moz://a. Or try moz://a/firefox. The extension's source code, and its list of URL mappings, is available at https://github.com/mozilla/moz-handler/.
If you think this add-on violates Mozilla's add-on policies or has security or privacy issues, please report these issues to Mozilla using this form.
Please don't use this form to report bugs or request add-on features; this report will be sent to Mozilla and not to the add-on developer.