ChartVersion returns the version of the helm chart from a helm repo server, by inspecting the repo's index.yaml.

GetContent uses go-getter (and Helm for OCI) to read the files from directories and servers.

GetManifestFromHelmChart downloads the given helm chart and creates a manifest with its contents.

New reads the fleet.yaml, from stdin, or basedir, or a file in basedir.

Options include the GitRepo overrides, which are passed via command line args.