${source.login}

Questions
1

I am trying to change to use JSON web token and am trying to change my application to use Client_secret_jwt. From what I’ve read, I can only change it with Json as seen on the following link.

https://developer.okta.com/docs/reference/api/apps/#set-swa-user-editable-username-password

What values are acceptable for ${source.login}?

"credentials": {
    "scheme": "ADMIN_SETS_CREDENTIALS",
    "userNameTemplate": {
      "template": "${source.login}",
      "type": "BUILT_IN"
    }

https://developer.okta.com/docs/reference/api/apps/#set-swa-administrator-sets-username-and-password