writes:

You mean like the FAA?

Yes, but I couldn't find a source for the certificate on the FAA site.

What has "not critical for me" to do with the issue ...

I explained why I made an exception for this certificate, something that
normally isn't a good idea.

... and if you want to know how to verify its origin you need
to hire a computer professional.

Not at all. You can do that without anyone's help.