newdude, I won't dispute what you say. However, I have to agree with nards444 that the Warranty Manual is very confusing on this matter.
On page 5 of my 2020 New Vehicle Limited Warranty manual, it specifically states under Diesel Components Coverage:
Exclusions: Excluded from the powertrain component coverage are sensors, wiring, connectors, engine radiator, coolant hoses, coolant, and heater core. Coverage on the engine cooling system begins at the inlet to the water pump and ends with the thermostat housing and/or outlet that attaches to the return hose. Also excluded is the starter motor, entire pressurized fuel system (in-tank fuel pump, pressure lines, fuel rail(s), regulator, injectors, and return line) as well as the Engine/Powertrain Control Module and/or module programming.
However, if you continue reading about the Federal and California Emissions warranties, later on page 24 it lists the components covered by these emissions warranties (below is a subset of the items which pertain to the fuel system).
Fuel Management System
AFM Exhaust Valves and Controller
Diesel Fuel Injection Pump *
Diesel Direct Fuel Injector and Rail *
HD Duramax Fuel Pressure
Regulator *
HD Duramax Fuel Pipes *
Fuel Injector
Fuel Pressure Regulator
Fuel Pressure Sensor
Fuel Pump Power Module
Fuel Rail Assembly
Fuel Tank Fuel Pump
Fuel Temperature Sensor
High Pressure Fuel Pump (SIDI)
If I am reading this correctly, the items listed above are covered under the Federal Emissions Warranty for 5yrs/50k miles. However, if you're in California or one of the several states that get the California Emissions Warranty, then the items above (like the Diesel Direct Fuel Injector and Rail) that are flagged with an "*" are covered for 7yrs/70k.
Once again, GM could not have made this more confusing. For some of these parts, they go from "specifically excluded" to 5/50 or 7/70 depending on where you live.