Here is a document with other third party certifications of the validity of the original document.
The full picture is quite complicated but a curious person has access to more than enough data to either make an informed decision or decide to trust no one.
The internet is full of sources that go deeper than what Apple thinks the general public is interested in.
Here is another PDF describe the security certifications. https://help.apple.com/pdf/sccc/en_GB/security-certification...
One could also start here with another third party review of the cryptographic process.
https://csrc.nist.gov/CSRC/media/projects/cryptographic-modu...
Here is a document with other third party certifications of the validity of the original document.
The full picture is quite complicated but a curious person has access to more than enough data to either make an informed decision or decide to trust no one.