3GPP 24.501 v20.0.0 — the document's own text
8.2.25.6 EAP message
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
This IE is included when the EAP Success message is sent as part of the EAP based primary authentication and key agreement procedure, as specified in clause 5.4.1.2.