Hi,
there are several misspellings deeply baked into standards like HTTP referer instead of referrer or seeked instead of sought… it would be nice to run some automated spelling checks before something become standard 
Have a nice day Ctibor
The Referer misspelling in a request header is explained all over the internet. A quick google search reveals the explanation in the Etymology section of the wikipedia page here.
Not sure about any other misspellings you mention, but the spec documents are located in repositories that can be updated. You can file issues there or even open a pull request to fix it on their behalf.
I think I have found the answer, words can be created if we don’t like how standard English words look or sound, reference: "Seeked" is not a word · Issue #3583 · whatwg/html · GitHub.
Thxfrcoop! 