3GPP 24.501 v20.0.0 — the document's own text
8.3.9.14 Serving PLMN rate control
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 when the network needs to indicate the maximum uplink control plane user data the UE is allowed to send per 6 minute interval.