What is the use of custom-artifact account

i am to understand the use of custom-artifact account in spinnaker.

I have a pipeline, where i want to pull a http file (a deployment manifest) as an artifact, and use it in deployment.

i use custom-artifact and put the url - (https://raw.githubusercontent.com/sdputurn/flask-k8s-inspector/master/Deployment.yaml) in reference.

I have tried running this pipeline multiple times, but i always fails with the error (Internal Server Error",“message”:“Custom references are passed on to cloud platforms to handle or process”,“status”:500)

i saw some tutorials where they just use custom artifact and put some use http to get files for deploy stage.