rfc4918 Also doesn't use the verbiage "content" it in fact says "contained instructions" and "request entity" which are not defined terms in either RFC you link

rfc4918 Also doesn't use the verbiage "content" it in fact says "contained instructions" and "request entity" which are not defined terms in either RFC you linked. > and the syntax of the request entity is correct (thus a 400 (Bad Request) status code is inappropriate) but was unable to process the contained instructions. Emphasis mine