docs: function normalizeComponents (options) {
  	  if (options.components) {
  	    var components = options.components;
  	    var def;
  	    for (var key in components) {
  	      var lower = key.toLowerCase();
  	      if (isBuiltInTag(lower) || config.isReservedTag(lower)) {
  	        "development" !== 'production' && warn(
  	          'Do not use built-in or reserved HTML elements as component ' +
  	          'id: ' + key
  	        );
  	        continue
  	      }
  	      def = components[key];
  	      if (isPlainObject(def)) {
  	        components[key] = Vue$3.extend(def);
  	      }
  	    }
  	  }
  	}