code: func InstantiatedPrepareAppUnitName(appName types.ACName) string {
  	// Naming respecting escaping rules, see systemd.unit(5) and systemd-escape(1)
  	escapedRoot := unit.UnitNamePathEscape(common.RelAppRootfsPath(appName))
  	return "prepare-app@-" + escapedRoot + ".service"
  }
docs: // InstantiatedPrepareAppUnitName returns the systemd service unit name for prepare-app
  // instantiated for the given root.