3GPP 24.501 v20.0.0 — the document's own text
8.2.7.24 Operator-defined access category definitions
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
This IE may be included to assign new operator-defined access category definitions to the UE or delete the operator-defined access category definitions at the UE side.