For now, I think existing exclaves such as the one that displays the camera indicator do not really apply to macOS (since MacBooks have dedicated hardware for that), but in the future there might be exclaves that do.
> since SPTM is not used according to Apple documentation:
Try reading that footnote again:
> Note 2: Page Protection Layer (PPL) and Secure Page Table Monitor (SPTM) enforce the execution of signed and trusted code on all platforms with the exception of macOS (because macOS is designed to run any code). All of the other security properties, including the protection of page tables, are present across all supported platforms.
It doesn't say macOS doesn't use SPTM. It says macOS doesn't use SPTM to prevent running unsigned code, since macOS is supposed to allow unsigned code (after the user jumps through some hoops).
For now, I think existing exclaves such as the one that displays the camera indicator do not really apply to macOS (since MacBooks have dedicated hardware for that), but in the future there might be exclaves that do.