Looking at the architecture document https://docs.prow.k8s.io/docs/overview/architecture/, I do not understand what controls the contents of this block in a PR on GitHub.

What adds required tests? Those do not come from ProwJobs, right? I have a mysterious one (pull-kubestellar-kubestellar-validate-prow-yaml) that I do not know where it is coming from (and I can not /test it).