I see this after typing in "brew doctor"
Warning: Some installed kegs have no formulae! This means they were either deleted or installed with
brew diy. You should find replacements for the following formulae:
python@2
What does this mean and how do I fix it?
It's just a warning, as most "brew doctor" messages are. Python 2 is dead. You can remove it with
brew uninstall python@2.