What is the meaning of the asterisk (*) when referring to Android XML resources? -

What does this Android code mean?

* is the difference between , + and empty:

  @ * android: id   
 Android_ics / packages / apps / Android such as: id / timeDisplayForeground "Android: layout_width =" wrap_content "Android: layout_height =" wrap_content "Android: singleLine =" set up / ridge / layout    
 
 
 * Allows you to use personal resources. Private resources are private for one reason because they can change their name in the future as part of the firmware or skin update  
 It is not a good idea to use these resources unless you have such an environment In which you know that these resources will not change your app in the future and will not break.  
 For example, personal resources are being referred by a system app, where you will see the most referenced references.