The advantage over service- or product-module-style resource is category hierarchy leveraged by (strict) membership tests, while documents (services & products) are typically not nested.\n
This base category is not intended to be used as a relationship rule definition, see "resource" Base Category for this.
<value><string>An HTTP Exchange represents at most one HTTP Request and one HTTP Response.\n
It does not specify exchanged data structure besides what is specified by HTTP. It may be HTML, SOAP, XMLRPC, ...\n
Most properties/category relationships are optional, but source, destination, resource, and at least one of request and response should be set.</string></value>