3GPP 24.501 v20.0.0 — the document's own text
8.2.7.41 Service-level-AA container
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
The network shall include this IE if the UUAA procedure is triggered for the UE supporting UAS services. The network may include this IE if there is a valid successful UUAA result for the UE in the UE 5GMM context upon a registration for UAS services is requested from the UE.