Programs written in legit are defined entirely by the graph of commits in a Git repository. The content of the repository is ignored.
legit is designed so that all relevant information is visible when running git log --graph --oneline.

For example, here is “hello world”:

You can find implementations of legit, as well as some example programs, on GitHub: https://github.com/blinry/legit. The entry in the Esolang wiki is at https://esolangs.org/wiki/Legit.