It really irks me that the de facto rate limiting headers mix camel case with the more standard dashes, i.e. RateLimit-Remaining instead of Rate-Limit-Remaining.

This irks me too, looking at the registry [1] it would definitely be an outlier.

[1] https://www.iana.org/assignments/http-fields/http-fields.xht...

At least it's not misspelled.

https://en.wikipedia.org/wiki/HTTP_referer

it's all lowercase anyway at parse time.