Operation. In particular o=P means that form uses POST method.
Session ID
SAML 2.0 mandated field name for relay state
SAML 2.0 mandated field name for SAML artifact
SAML 2.0 mandated field name for SAML response, especially in POST profile
SAML 2.0 mandated field name for SAML request
SAML 2.0 mandated field name for signature algorithm in redirect binding
SAML 2.0 mandated field name for signature in redirect binding