After reinstalling OSX, applications (Parallels) still recognize the computer, why?

Question

macOS

Half a year passed, and through CMD + R erased the hard drive and completely installed OSX.
Then I installed a trial version of Parallels 11, and it tells me that it has already been installed on this computer and that you will not receive a trial period from us anymore!
Naturally, I’m shocked, not because they won’t give a trial period, but because: How the hell did they recognize my computer?

Answer 1

* mac-address of the device (this does not mean that it is poppies, which means - by hardware)
* mac-address of the network card / WiFi
* UDID / Device serial number
* by ip (and through ip - region, city, time, etc.)
* fingerprint of the browser and/or comp
* combinations of the above.