How does one ascertain what the components of RFC 3615's examples represent?

Question

The SWIFT URN namespace declaration RFC (https://datatracker.ietf.org/doc/rfc3615/) provides

1. urn:swift:xsd:epp$mi.i-2.0 and
2. urn:swift:type:fin$103

as examples, yet does not explain what the short phrases

1. xsd

2. epp

3. mi.i-2.0

4. type and

5. fin$103

specifically represent, in contrast to all alternative RFCs I've had the previous pleasure of reading. Although it is mentioned that

the URNs in this namespace are opaque

I've no knowledge either of what this means, and have been unable to locate any standardized terminology referencing this term, so I don't know whether the information I desire is deliberately unavailable, or even unavailable.

Is there any feasible way for me to ascertain how to accurately create an RFC 3615 compliant URN other than guessing? Thus far I have estimated that xsd and type probably refer to BICs, and their successor epp and mi.*s refer to IBANs, but this doesn't appear correct based upon the more complex examples provided by the RFC.

Thanks for any responses.