>It’s not burned into the BIOS, instead Microsoft maintains a database mapping licenses to hardware identifiers.

Wrong. IT IS 100% stored in the UEFI firmware, specifically ACPI tables, MSDM field. Only if that exists, it is then verified on-line for activation to make sure the license is genuine and matches the device ID you're referring to for witch the license was sold(typically for OEM) or if it's portable.[1]

On linux you should be retrieve the license via something like:

  sudo strings /sys/firmware/acpi/tables/MSDM

  sudo acpidump | grep MSDM