$DOCKER_CONFIG on Windows

[realflash]

In the README I see:

If credentials are required, buildctl will attempt to read Docker configuration file $DOCKER_CONFIG/config.json. $DOCKER_CONFIG defaults to ~/.docker.

Where is this on Windows (11)? Where can I look up what should go in this file? Is it standard Docker configuration? It's not mentioned in this README or in the one specific to Windows.

[realflash]

On Windows this defaults to
%USERPROFILE%
, probably
c:\Users\yourusername

The best way to populate this file is to run
nerdctl login <registry-dns-name>
You'll be prompted to authorise and the creds will be saved in the relevant file for you.