- It's weird that only one type of comment works. Any type of comment in any type of language at the end of a file on its own line that starts with `# sourceMappingURL=` should work.
- In reality, source maps are only used by JavaScript and CSS. It would be really nice if tools working with source maps didn't have to care whether a file is CSS or JavaScript. If it wants to add a sourceMappingURL it can just add `\n/*# sourceMappingURL=... */` and be done with it.
- Firefox already supports it. (Chrome is a bit weird: It allows either `//#` or `/*\n//# ... \n*/`)