HTTPS does not mean that a message came from the particular server you assume it does. For example, most CDNs will be acting just like a MITM in order to operat

HTTPS does not mean that a message came from the particular server you assume it does. For example, most CDNs will be acting just like a MITM in order to operate. Having a separate signature that can verify the HTTP _content_ is from the origin server, regardless if it gets re-encrypted by other services en route, is probably useful.