get groupItem() {
      return true;
    }
@class
The <code>ui5-li-groupheader</code> is a special list item, used only to separate other list items into logical groups.

@constructor
@author SAP SE
@alias sap.ui.webc.main.GroupHeaderListItem
@extends sap.ui.webc.main.ListItemBase
@tagname ui5-li-groupheader
@implements sap.ui.webc.main.IListItem
@public