You can use this reques to download the config version file of a specific application, you also need the specific config ID and the version ID, if you want to download the template file, then you need the template ID as the last path field, if you want to download the version file, then you need the version ID as the last path field:
curl -i -X GET \
-H "Authorization:<your-authorization-token>" \
'https://<your-iem-url>/portal/api/v1/applications/{your-app-id}/configs/{your-config-id}/template/{your-template-id}'
A successful response looks like this:
you may get a file named like config.json