Is this based on Auto Trash?
I wrote most of this before knowing of Auto Trash. I originally used a different format for the blueprint. I read Auto Trash as soon as I learned of it of course, and I remember adding 1) an error message if the force doesn't have logistic bots unlocked, and 2) that I can get the combinator's slot limit (20) from entity_prototypes instead of hard-coding it, because I saw these in Auto Trash.