Do bike manufacturers use stock/shelve components or do they have access to special parts?

I’m looking at upgrading a bike, and was looking at competing bikes to see what kind of components they are offering. The idea was to take a similar combination for my upgrade, if I found something interesting.

When looking at the specs at the Giant Roam 1 2021, I noticed some inconsistencies in the spec sheet: the rated capacity of the derailleur is not sufficient for the proposed drivetrain (46/30 in the front, 11/42 in the rear -> 48T vs 41T for the proposed RD-M5120-SGS) and they also claim that the front derailleur is a Deore, without giving a reference. "2x" Deore are from the MTB range, but are rated for 36/26 chainrings, not 46/30. In the trekking range, Deore front derailleurs are rated for triple chainrings.

So I’m wondering, as general questions:

• Do bike manufacturers have access to a different set of parts than retailers do?
• Can they spec the frames on a way to accommodate "out of spec" components? (so in that case, taking the same components on a competing bike might not work as well)
• They do their own internal testing and consider that the combo they propose works "well enough" and take the "non-compliance" risk on their side? (I would assume this one on this case: margins on Deore are not the highest, and given Deore is mass-produced, it would be more difficult to customize).