If the web server is following RFC 8969, it will treat "referrer" as "referer" and throw a 397 TOLERATING to let you know you should change it to the latter on

If the web server is following RFC 8969, it will treat "referrer" as "referer" and throw a 397 TOLERATING to let you know you should change it to the latter on your end. See Section 3. https://pastebin.com/TPj9RwuZ https://pastebin.com/TPj9RwuZ (Yes it's my April Fool's RFC.)