Or you're any of the hundreds of organizations that are known to have root or intermediate CA certificates. E.g., the former government of Tunisia.

Or any of the unknown number of intermediates who are not known.

This is only the case if those root certificates are installed on the Playstation. I'm not sure if we know which ones are.

For the purposes of PSN they'd only need Sony root certificates, but I expect that they have others for general web browsing.

My guess is they have a large-ish set of root certs like every other SSL/TLS library, but one or more may be marked 'magic' in some way. Plus they'll probably want the option to utilize third-party CDNs at some point which often implies a common CA.

Given the rest of what's known about their design I doubt they've deliberated it at a particularly high level in their organization. Or at least, high enough where management doesn't see the benefit of maintaining their own trust root and is glad for the opportunity to outsource something critical.

I believe it's lieutenant :) (I have seen that film far, far too many times)

Good. I posted that before they updated their post to clarify that they were sending data over SSL. It doesn't sound like the issue is as bad as they had originally insinuated.