BPDU (Bridge Protocol Data Unit) is used by Spanning Tree Protocol (STP) and its variants (like RSTP) for bridge communication. BPDUs are Layer 2 frames; they don't have an IP header and, therefore, don't use an EtherType value in the same way as IP packets.
However, BPDUs do have a specific MAC destination address that helps network devices recognize and process them. The MAC destination address for STP BPDUs is 01:80:C2:00:00:00.
So, while BPDUs don't have an EtherType like IP or ARP packets, the special MAC destination address effectively serves a similar purpose: identifying the frame's content and ensuring it's processed correctly by devices that understand STP.