From Wikipedia:
One of the key reasons why Rosetta 2 provides such a high level of translation efficiency is the support of x86-64 memory ordering in the M1 SoC.[12] The SoC also has dedicated instructions for computing x86 flags.
So, Apple always adds one more thing to their hardware to enable their magic.
[0]: https://en.wikipedia.org/wiki/Rosetta_(software)#Rosetta_2
you can find more apple-specific stuff by digging around in these docs: https://asahilinux.org/docs/platform/subsystems/