A chart is a directory (or .tgz) of Go templates, default values and metadata. A release is one named installation of a chart in a namespace; install a chart twice and you get two independent releases. A repository publishes charts: an HTTP server with an index.yaml catalog (helm 29,435 repo add) or, since Helm 3.8, any OCI registry (oci:// URLs). Artifact Hub 112,249 (artifacthub.io (https://artifacthub.io 112,249 )) indexes both.
Helm 3 dropped Helm 2's in-cluster server, Tiller: the CLI uses your kubeconfig, so RBAC applies to it as to kubectl 5,150 . Every install, upgrade or rollback writes a revision, a Secret of type helm.sh/release.v1.