RequestFacts
The standard request facts: the keys of a Command's headers the framework itself fills, beside those the host lists, written into the committed event stream with them. No request header sets one (the trust boundary): the edge records each from what it knows.
APP_ID, the calling application, the app of the caller its resolver authenticated; none for a caller without one.
REMOTE_IP and USER_AGENT, the client's address and
User-Agent, on the public port alone.
A command a server derives (a saga's, an @OnRejected or @OnCommitted handler's compensation, a timer's) has no request of its own: it inherits the facts of PROPAGATED from the event stream it derives from, and only those, as 9.x propagated the application.
Properties
The facts a derived command inherits from the event stream it derives from: what the request was made for, not where it came from, so REMOTE_IP and USER_AGENT stay with the request that had them.
The client's User-Agent.
Functions
The facts of headers a command derived from them inherits (PROPAGATED).