New version does not just support Firefox 68 (firefox-esr in Alpine 3.12),
which is going to be EOL soon. It also supports the new ESR 78
(firefox-esr in Alpine edge, soon also in 3.12, supported until ~2021-04)
and 79 (current stable "rapid release" version; firefox in Alpine edge).

The source was moved to a dedicated git repo, so other distributions can
also use it. Keep the distro-specific links here in a separate HTML
file, so they can be modified without changing
mobile-config-firefox.git.

Related: https://gitlab.com/postmarketOS/mobile-config-firefox