WSL 2 mac address filtering
Solution 1:
Short answer: Almost certainly the MAC of the wireless adapter.
Explanation:
WSL2 networking runs on a virtual network card (the "vEthernet" where the "v" is for "virtual") that is NAT'd (Network Address Translation) behind the Windows host's physical card. This is similar to the way a router in your home will typically provide a single address (and MAC) for all of the computers and devices behind it.
The only MAC/address that the network you are connecting to will see is that of the host's Wireless adapter.