Open an English dictionary (the Oxford one if you're serious), and come back. Note my fault if tbl didn't know how to speak English corectly backed then.
Surely whether or not the RFC's authors know how to spell a word has no bearing on how sensible it is to correct the spelling of "HTTP_REFERER"? I mean, if dools had said "HTTP referer" then you might have had a point, but "HTTP_REFERER" unambiguously refers to the name of the header field.