Have you ever noticed misspelled HTTP response headers?

$ http -h http://www.dmoz.org/Computers/Programming/Languages/Python/Books/
HTTP/1.1 200 OK
Connection: close
Content-Encoding: gzip
Content-Language: en
Content-Length: 9907
Content-Type: text/html;charset=UTF-8
Cteonnt-Length: 33416
Date: Tue, 12 Apr 2016 12:26:06 GMT
Server: Apache

That ‘Cteonnt-Length’ sure looks weird!

According to this StackOverflow answer, the jumbled header contains the uncompressed size of the response and, sure enough, it does seem to be the case. But why?

It seems like this is a trick employed by hardware appliances (eg Citrix NetScaler) to ‘remove’ a header without affecting the check-sum value.