PRG1/PRG0 for NES ROMs

[xamenus]

What do PRG1 and PRG0 mean for NES roms? The GoodNES utility gives some roms this extra description. Is one of them a newer version than the other or what? Thanks.

 

[Teamz]

no it's the size of the program code inside the rom

 

[xamenus]

no it's the size of the program code inside the rom

So neither one is better than the other, then?