3GPP 24.501 v20.0.0 — the document's own text
8.2.7.54.2 Extended LADN information
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 UE supports LADN per DNN and S-NSSAI and there are valid LADN service area(s) for the subscribed DNN(s) of the UE and S-NSSAI associated with the LADN in the current registration area.