Items And Loot Archive

I am curious about the "repair" function in the game. What constitutes a "broken" weapon and what is a "damaged" weapon? I am curious because my mods say I can "repair a broken or damaged item) , but what I know as a "broken" weapon won't even allow me to TRY and repair it. I am looking for a thorough explanation by a DEV team member on what is the repair mod, what is the specific repair mod (like weapon repair, armour repair, etc), and what is the force repair mod. what do they do? how much do they affect things (is it actually worth getting these mods)? i think we just need more of an explanation on this function of the game.