3GPP 23.501 v20.2.0 — the document's own text
5.7.2.8 Maximum Packet Loss Rate
Taught in 14. What the network promises (The 5G system architecture, in depth), 5. The connection, and what is promised on it (The 5G system architecture, overview).
The Maximum Packet Loss Rate (UL, DL) indicates the maximum rate for lost packets of the QoS Flow that can be tolerated in the uplink and downlink direction. This is provided to the QoS Flow if it is compliant to the GFBR
NOTE: In this Release of the specification, the Maximum Packet Loss Rate (UL, DL) can only be provided for a GBR QoS Flow belonging to voice media.