Like virtualized NICs pretending to be an NE2000? That's interesting, do you know why they'd use a G200 and not something like an older ATI chip?

Drivers, probably.

Probably started out as a real G200 chip which might’ve been the cheapest and easiest to integrate in the 2000s? Or it had the needed I/O features to support KVM (since this would’ve involved reading the framebuffer from the BMC side), or matrox was amenable to adding that.