[maccard]

And sometimes that mistake propagates and leaves us 25 years later still using referer [0]

[0] https://annaken.github.io/a-brief-history-of-the-referer-hea...

[dmurray]

This one always seemed to me like a plausible alternative spelling (cf. traveler for traveller).

Maybe the reviewers who let this through were speakers of British English who knew it was misspelt but conceded it without a fight, having already lost on color, gray, center...

[thaumasiotes]

Traveler is stressed on the first syllable; referrer is not.