Modifications To Default Scripts

I have a couple of programs that are custom versions of the built in programs, with minor changes. For instance I have a version of excavate that goes upwards for felling trees and stops when it finds a layer in which it encounters nothing.

Since the copyright for the original script belongs - I assume - to Dan, what is the policy on me posting my variants?

Absolutely fine for people to do anything with the lua they like, it's yours to play with.