WMI (Windows Management Instrumentation) is the standard Windows interface for asking the system about itself. Any program can query it for details about the BIOS, motherboard, processor, disks and network — which is exactly why anti-cheats and licensing systems like it.
What WMI exposes
A few WMI queries return a detailed hardware picture: BIOS and motherboard data, disk information, network adapters, CPU details. It is convenient for software that wants a fingerprint, because a lot of the profile is available in one place.
WMI is a window, not the source
This is the key point: WMI does not invent these values — it reports what the underlying sources hold. The BIOS serial it returns came from SMBIOS; the network details came from the adapters. WMI is a unified view over the registry, firmware and drivers.
What this means for an HWID change
Because WMI just reflects the underlying values, changing your HWID properly means changing those underlying values — not only what WMI happens to report. HWIDChanger changes the genuine identifiers it can safely change — Windows IDs, the disk volume serial, MAC — so WMI reflects the new values consistently. And it is worth knowing the honest limit: values that come from firmware, such as the SMBIOS UUID, are not changed by software, so WMI keeps reporting the real ones for those, and a strict anti-cheat that reads firmware directly sees them too.