Do you mean the way Manjaro gets it from the AUR? I guess what you mean is from a repository?
Maybe the Mint developers will also add Pale Moon to the Mint repos if you request it--it can't hurt to ask!
The debianized sources are available here:
http://download.opensuse.org/repositori ... ntu_16.04/Though if the "lsb_release -cs" command in a Mint distro results in a distrelease name that's not listed in the debian/rules file and the default gcc version is greater than 4.9, they'll have to add that result to the list for the auto distrelease detection to work correctly.
By the way, I've used what I learned with the distro detection in PM to have some other programs that can build on either Qt4 or Qt5 automatically use which version is going to work better for the user-- Qt4 if Qt5 isn't >= 5.4. Examples would be SMPlayer, SMTube, and CopyQ.