EIdHTTPProtocolException = class(EIdReplyRFCError);

EIdHTTPProtocolException is a EIdReplyRFCError descendant that represents an exception type raised by the HTTP protocol handler during processing of an HTTP response. EIdHTTPProtocolException is generally raised when an unexpected numeric HTTP response code is received from the HTTP response. 

EIdHTTPProtocolException reimplements the alternate constructor CreateError to facilitate creating an exception instance with the values specified in the arguments to the constructor. 

EIdHTTPProtocolException also implements ErrorMessage to describe the text in the protocol error message.