{
    "type": "external_account",
    "audience": "//iam.googleapis.com/projects/$PROJECT_NUMBER/locations/global/workloadIdentityPools/$POOL_ID/providers/$PROVIDER_ID",
    "subject_token_type": "urn:ietf:params:oauth:token-type:saml2",
    "service_account_impersonation_url": "https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/$EMAIL:generateAccessToken",
    "token_url": "https://sts.googleapis.com/v1/token",
    "credential_source": {
        "file": "/var/run/saml/assertion/token"
    }
}