WINDOWS 10 activated automatically without a license?

I recently formatted my old PC. When I installed Windows on my hard drive via bootstick. During the installation you are asked for the license key, but I continued the installation without entering it.

When I set up my PC and looked under Settings → System and Update → Activation, it said: "Windows was activated by a digital license linked to this Microsoft account.

Also by the command: "slmgr / xpr" in Windows cmd I was told that Windows is permanently activated.

My question now is how can that be?

I have never owned windows through this Microsoft account. Could it be because the Microsoft account is the one on my xbox one and that automatically activates windows?

Windows recognizes that it was already installed on the PC.

Does it automatically in the background over the Internet. Microsoft virtually remembers your pc

If you did not use a Microsoft account: The license is stored in your BIOS. So even if you reinstall, change hard drive, etc. Windows remains activated.

https://www.heise.de/...30353.html

You can read more about it here.

However, if you've ever used a Microsoft account, the key will be "linked" to it.

Is stored in the bios.