From original Phenoms (if not earlier?) to Ryzen, passing through Bobcat and Bulldozer, *a lot* of exoteric issues happened in light of it. Not seldom system critical. Therefore in my opinion it would be really important to log such datum (and perhaps exposing it to applications, and system in general too). Originally, on my old E-350 system, I thought you could just find it easily in low memory (around 0x000C8000-0x000EFFFF rom area), and end of the story. But on my "newer" E-450 that's seemingly not mapped anymore. Windows utilities such as AIDA64 and CPU-Z still seems able to access its version somehow, so I know there must be at least another one method that you could do it. Unsure what it is though.
I spoke with the HWiNFO developer, and he told me he pulls this out by scanning the high BIOS memory area.