If you search the code, they support Rosetta, which means an ARM Linux kernel running x86 container userspace with Rosetta translation. Linux kernel can be told to use a helper to translate code using non-native architecture.

Actually, they explain it in detail here: https://github.com/apple/containerization/issues/70#issuecom...

It's unclear whether this will keep being supported in macOS 28+, though: https://github.com/apple/container/issues/76, https://www.reddit.com/r/macgaming/comments/1l7maqp/comment/...