Bugzilla#1220143, Relevant (though unclear) spec in UI Events

Focus on this button and press Space or Enter:

Expected: alert button gets focus.
Actural: alert button gets focus and was clicked.



  
  

  
  


  
  

    
      

        
        Firefox 74
        Chrome 80
        Safari 13
      

    
    

      Pressing Space on #focus triggers click on #alert
(via keyup?)		
      Yes
      No
      No
    

    

      Pressing Enter on #focus triggers click on #alert
(via keypress?)		
      Yes
      Yes
      Yes