C trigraphs is a great example that I forgot, because no one uses it and everyone hates it; glad to hear that C23 is finally removing that wart. I'm not aware of other languages with Java-style escapes before tokenization. I only learned the Java example due to the book Java Puzzlers; it has little impact on real-world code because it's considered obfuscation. I don't know the nitty-gritty details of other programming languages that I come in contact with; I just know Java especially well.