"Discover" Rancher API URL from inside a Kubernetes Pod?

(I’m ware of How to access Kubernetes api from outside of Rancher and its answer, to paraphrase, “there ain’t”)

Since Rancher 2.x now supports Helm: are there any Rancher labels, annotations, or chart variables that I could use while installing a catalog app into my cluster which would tell the app which Rancher cluster it gets installed into?