Text description (for those with screenreaders):
A portion of a prime number checker written in the Rust programming language, where the first few lines are written correctly including the first if statement in the program. However, the following if statements are written using Python syntax instead of Rust, as the author slipped back into his native tongue.
I'm not sure what does and doesn't control it, but I've installed nano on some Linux distros and it has no syntax highlighting at all, then other distros (currently using LMDE) just have it by default.