The name of the credentials field inside the component.json is used to access OAuth data during the component execution. If for example the field was set to be myOAuth inside the component.json then the credentials would be like:

{
     "myOAuth":  {
       "access_token":"2YotnFZFEjr1zCsicMWpAA",
       "token_type":"bearer",
       "expires_in":3600,
       "refresh_token":"tGzv3JOkF0XG5Qx2TlKWIA"
     }
}