Nonstandard subnational flag emoji: An answer!

So, remember this ? Well, I finally found out where it's coming from! What's going on here is that these flags are included in my system's emoji font, which is from Google's Noto Emoji family. And the version of this font included with Debian and Ubuntu, at least, includes these nonstandard flags. Which ones? Well, the files for them are right here ! And yup, it's exactly the ones I said. So yay,…