3GPP 24.501 v20.0.0 — the document's own text
8.2.6.17A Payload container type
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
This IE shall be included if the UE includes the Payload container IE.
NOTE: In this version of the protocol, the Payload container type IE in the REGISTRATION REQUEST message is set to "UE policy container" as described in clauses 5.5.1.2.2 and 5.5.1.3.2.