The usage of `REACT_APP_SECRET_CODE` in [Adding Custom Environment Variables](https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables) is misleading given that there are no secrets in the front end. Should I open a PR that changes all to `REACT_APP_NOT_SECRET_CODE`? Also, should there be a warning box toward the top about being careful not to expose secrets?