Neither is a subpanel, BrElder.
Looks to me like:
The service conductors are tapped with the big split bolt connectors, and the wires come right into the LOAD side of the Square D 2 pole breaker enclosure
in PARALLEL with the 2 Romexes. If you"ll look at the last pic, you can see that the bare equipment grounds from the romexes were tapped into the service neutral, and paralleled into the panel's neutral bar.
If you really see things like this, you might consider contacting the CSLB about some disciplinary action being taken against the EC's that do this kind of work.
Morons that do work like this can kill people.