Honest question: Wouldn't a Decider/Arithmetic combinator already accomplish the same purpose? A Decider set to output everything if anything is greater than 0, or an Arithmetic Combinator set to multiply everything by 1? Or would those not be able to output per colour channel? This isn't criticism, just an attempt to understand what the mod does.

They do. There is another mod and I use that extensively in my blueprints and it was not updated for a long time to 2.1. So I made one to be able to update my old 2.0 saves to 2.1. If you start a new game, you can do what the mod does with a regular combinator (the diode combinator is just an arithmetic combinator in a trenchcoat).

Ah! OK, got it. Thanks for the explanation.