When I work in my own repositories these days, I always add a Nix flake to the repo so that I can spin up a working development environment on any system with a single command. What do I do when I’m working in someone else’s repo and they don’t want to adopt Nix flakes? Normally, I’d just add the file to my copy of the repo and gitignore it locally so I don’t commit my personally-specific files with the rest of my changes.