Where do Hybrid mode registration saves credentials at for windows host?

[mingtao Sun]

I'm launching hybrid SSM instances (for EC2 instances) and I tried to use the SSM instance role attached to do some addtional stuff like putting stuff to parameter store. According to the doc: https://docs.aws.amazon.com/systems-manager/latest/userguide/ssm-agent-technical-details.html, Linux SSM agent store credentials at /root/.aws/credentials. I could verify they exist. However, I was not able to find any credentials for windows host. The C:\Program Files\Amazon\SSM\credentials is empty and C:\Users\Administrator\.aws\credentials\ also has no stuff (I created this prior to SSM installation to verify if they write stuff to the file).
I could verify the SSM instance role is being used while running .\ssm-cli.exe get-diagnostics --output table

AWS Credentials                      │ Success │ Credentials are for                                                                     │
│                                      │         │ arn:aws:sts::xxxxxx

Do we have a way to obtain that credentials or use that role directly?

Thanks