PHY ID value

From: orbit <ordinarybit_at_proton.me>
Date: Mon, 07 Oct 2024 13:04:59 UTC
Hi,

In the miidevs file here https://cgit.freebsd.org/src/plain/sys/dev/mii/miidevs, there are list of OUIs and PHYs. OUIs are easily obtained as unique identification of a vendor or manufacturer but how do the PHY ID values were obtained? Let's say for example, the 0x0020 value of Realtek RTL8201L PHY?

BR,
orbit