How can I contribute to the docker-compose bootstrap script?

I have found a bug in the docker-compose startup script. This is the (bash) script that is to be used when one wants to run docker-compose as a container. (Install Docker Compose | Docker Documentation → alternative install options – > Install as a container →

I just can’t find this file on GitHub so that I can fork and submit my fix for it. How could I get further with this?