Please tell me about registration (American Truck Simulator)

The official wikipedia on modding from SCS has such a page on registration:
https://modding.scssoft.com/wiki/Documentation/Engine/Units/accessory_data
I'm interested in the following points:

overrides - Each array member specifies a path to an accessory definition file which is applied to the vehicle, overriding other accessories of the same type if one already exists on the vehicle. This eliminates the need for suitable_for / defaults relationships in most cases (eg engine badges and sounds). (New in ETS 1.27 / ATS 1.6)

require - Each array member specifies an accessory type that must exist on the vehicle while this accessory is installed. For example, if a truck has separate accessories for mudflaps and mudflap hangers, each hanger accessory might declare require []: mudflaps to disallow a state where the truck has mudflap hangers but no mudflaps. The token is the final segment of each unit name, so matching accessories would have unit names like foo.bar.mudflaps.
Note: Every required accessory type should always have a corresponding accessory of that type in defaults!

How tx can be implemented in registration. Overrides seems to have figured out how to use it (although not completely), Require did not understand at all. I ask you to tell me what and how if someone knows, preferably with examples of registration, of course I tried to translate (this is for those who say, but did not try to translate?), But still did not understand where to get or how to make foo.bar.mudflaps