So there's this standard called ISO 3166-1 alpha-2 that defines a 2 letter code for every country on the planet (like ME = Montenegro) and a bunch of places that aren't countries (like EU = European Union). You've probably encountered such a code before in top level domain names (.im belongs to the Isle of Man) and on Discord (typing :flag_fm: yields a 🇫🇲 emoji).

One of these codes is RS (= Serbia). Either by a sheer coincidence or someone playing 5D chess, .rs is also the file extension for the Rust programming language, which is why the domain name of every other Rust project now belongs to Serbia. This made me curious about other cases like this, so here's an incomplete list of programming languages, domain-specific languages, markup languages, etc which file extensions match a country code. If you think something is missing, let me know!