How does Forgotten Queens modify anything without touching the base files?

[Pale Blue]

Hi i try to understand how the forgotten queens mod works. They dont seem to edit any base files or at least very few. Thats great for compability with other mods and i try to understand how they do it.
From what i could grasp with my limited modding knowledge they seem to do most of it with some kind of modifiers and triggers.

Can someone explain me how exactly they do for example modify the base output of a farmer by +1 food without changing the pop jobs file?

 

[AlphaAsh]

It creates a custom modifier, by first editing the necessary job in economic categories to support the modifier.

I do the same thing in AlphaMod for quite a few jobs I want to create custom modifiers for.

planet_farmers = {
    parent = planet_jobs
    generate_mult_modifiers = {
        produces
        # upkeep
    }
    generate_add_modifiers = {
        produces # This one
        upkeep
    }
}