Is somewhere a good explanation on how

.get

on resources works and where it gets its data from? Does it query information from the state in the current stack, can I query other stacks, does it call the provider APIs to figure out the information? I need to get some info about an existing GKE cluster, similar to what I would do with “data sources” in terraform https://www.terraform.io/docs/providers/google/d/google_container_cluster.html.