IIUC this is based on a pretty simple fingerprint of the executable. So a motivated attacker can produce different builds that break the signature resulting in

IIUC this is based on a pretty simple fingerprint of the executable. So a motivated attacker can produce different builds that break the signature resulting in each build being "new" and being allowed by default. This is different than the "notarization" process which requires uploading the executable and Apple has a change of better identifying variants. I don't think notarization is yet required or done on unknown executables by default. (In fact I think they need to be signed to be notarized.)