Support for multiple .env file.

I say, if you put a file with the secrets for production on your development machine, it is dangerous practice.
You should not do it, and you should not know the secrets as a developer.
The secrets should be accessible only by a server admin.

In the ideal world, yes, but in reality, the roles are often more complex. 
But ok, finally, it's not very serious, it's a detail. Forget it then.