That’s still not as bad as having to spell referrer wrong in http headers where it’s spelled “referer”... which is incorrect for every flavo(u)r of English.
I remember writing a logging method for a webserver forever ago, and could not for the life of me, understand why my Referrer values were not getting logged.
Finally looked at the headers, and thought it was a bug in the browser I was testing. Took way too long to figure out the problem.