The firefox package is currently broken in armhf Alpine, and it looks like fixing will take a while (depends on packaging rust for armhf on Alpine): https://bugs.alpinelinux.org/issues/7409 https://github.com/alpinelinux/aports/pull/1578#discussion_r119988654
Later, the aports folder will probably get split up in its own repository. But right now this is simply convenient.