What is the network interface 'llw0'?
llw is a WLAN low-latency interface, and llw0 is simply the first of those.
The llw interface is a network interface that comes from a nexus defined in the Skywalk system. You can look it up like this:
skywalkctl list-providers | grep llw

You'll see that it is handled by a BCM &quot;driver&quot; (i.e. an IC in your computer manufactured by Broadcom).
The interface is supposed to be there - it is not a bug.
Similar to how awdl (that you mention) is a special kind of WiFi connection that is peer-to-peer and low-latency (used for AirDrop for example) - llw is also a special kind of WiFi connection that is low-latency (no power saves allowed), but with an access point.