The following is an excerpt from RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1:
Content-Lengthentity-header field indicates the size of the entity-body, in decimal number of OCTETs, sent to the recipient or, in the case of the
HEADmethod, the size of the entity-body that would have been sent had the request been a
. And this is my first time seeing this structure of a noun phrase:
the entity-body that would have been sent had the request been a
. The meaning would be:
the entity-body that would have been sent if the request had been a
, but how come? What has been omitted here? Is it an inversion? What grammatical concept is used here?