The Mozilla Archive Format add-on is no longer maintained since September 5, 2018.
Historical archive of the Mozilla Archive Format add-on
While the Mozilla Archive Format add-on is no longer maintained, the final version released in 2018 can be installed offline on Firefox 56 to convert saved pages to other file formats. Using outdated software can result in security vulnerabilities and may corrupt user profile data, hence this procedure should only be followed by experienced users on a separate computer that is not connected to the Internet.
Previous versions of the add-on and their changelog are also available as a historical archive. Some versions of the add-on can only be installed on pre-release versions of Firefox after disabling the signature requirement. The XPI packages contain the original source code as well as information about which Open Source and Free Software license applies.
The Mercurial version control repository can be downloaded with the command:
hg clone http://hg.mozdev.org/maf/