VS Code with Git
Phew. I closed a python project without realising that the requirement.txt file had deleted its content leaving a v, because fat fingers didn't press the CTRL-key. Oh, and I have autosave enabled as it makes life easier with it than without it.
Thankfully with Git I was able to revert back to the previous version.
Okay, it wouldn't be the end of the world to run another
pip freeze > requirements.txt
But it does mean I can rest easy if it happens again knowing that version control does what it says within vs code.