code: func hideCaddyfile(cctx caddy.Context) error {
  	ctx := cctx.(*httpContext)
  	for _, cfg := range ctx.siteConfigs {
  		// if no Caddyfile exists exit.
  		if cfg.originCaddyfile == "" {
  			return nil
  		}
  		absRoot, err := filepath.Abs(cfg.Root)
  		if err != nil {
  			return err
  		}
  		absOriginCaddyfile, err := filepath.Abs(cfg.originCaddyfile)
  		if err != nil {
  			return err
  		}
  		if strings.HasPrefix(absOriginCaddyfile, absRoot) {
  			cfg.HiddenFiles = append(cfg.HiddenFiles, strings.TrimPrefix(absOriginCaddyfile, absRoot))
  		}
  	}
  	return nil
  }
docs: // hideCaddyfile hides the source/origin Caddyfile if it is within the
  // site root. This function should be run after parsing the root directive.