I used a create-react-app.
And created environment variable files. .env.local, .env.development.local
I found that .env.development ispreferred over .env.local
And env.development.local seems to have prioty over .env.development.
If so, .env.development.local is used to override .env.development what is the purpose of .env.local?
In .env.local you can set up environment variables that are specific to your local machine and it doesn't have to be on development mode to work, so variables there will work for both development and production.