I'm using a Ubuntu 16.04.6 LTS version.

The xprop output is:

XdndAware(ATOM) = BITMAP
_NET_WM_ICON_GEOMETRY(CARDINAL) = 1925, 737, 54, 54
WM_STATE(WM_STATE):
		window state: Normal
		icon window: 0x0
_NET_WM_DESKTOP(CARDINAL) = 0
_NET_WM_STATE(ATOM) = _NET_WM_STATE_MODAL
WM_HINTS(WM_HINTS):
		Client accepts input or input focus: True
		Initial state is Normal State.
		bitmap id # to use for icon: 0x6c00376
		bitmap id # of mask for icon: 0x6c0037c
		window id # of group leader: 0x6c00001
_GTK_MENUBAR_OBJECT_PATH(UTF8_STRING) = "/com/canonical/unity/gtk/window/1"
_UNITY_OBJECT_PATH(UTF8_STRING) = "/com/canonical/unity/gtk/window/1"
_GTK_UNIQUE_BUS_NAME(UTF8_STRING) = ":1.265"
_NET_WM_ICON(CARDINAL) = 	Icon (22 x 22):
	                      
	                      
	                      
	      ░░    ░░░░      
	    ░░  ░   ░░░░▒░    
	  ░░    ░░ ░░  ░░ ░░  
	  ░      ░░░░░ ░░  ░░ 
	 ▒       ░▒▒▒░░░    ░ 
	░░       ░▒ ░▒░░░░  ░░
	░░ ░    ░ ▒▒▒░ ░░   ░▒
	▒░░     ░ ▒░░░░░░  ░░▒
	▒░░   ░░░ ▒░░░░░░  ░▒▒
	▒▒░  ░░░░░▒▒▒▒░░░  ░▒▒
	░▒░    ▒▒▒▒ ░▒░░░ ░▒▒░
	 ▒░░  ░▒▒▒▒▒▒░ ░░ ░▒▒ 
	 ░▒░░░▒▒▒▒░▒░░░░░░░▒░ 
	  ▒▒ ░▒▒░▒░▒░░░░░░▒▒  
	  ░▒▒░░ ▒▒░▒▒░░░░▒▒░  
	  ░▒▒▓▓▒▓▒░░▒▒▒▓▓▒▒░  
	   ░░░▒░░   ░░░▒░░░   
	                      
	                      

	Icon (16 x 16):
	      ░░        
	   ░░░  ░       
	  ░     ░░      
	 ░      ░░      
	 ░       ░▒▒▒░  
	░░      ░░░  ▒  
	▒       ░ ▒▒▒░  
	▒░░       ░     
	▒░░   ░░░ ▒     
	▒▒░  ░░░░░▒▒▒░  
	▒▒░   ░▒▒▒▒  ▒  
	 ▒░░  ▒▒▒▒▒▒▒░  
	 ▒▒░░░▒▒▒▒      
	  ▒░ ░░▒░▒      
	   ░▒░░ ▒░      
	     ░▒▒▒       

	Icon (24 x 24):
	                        
	                        
	                        
	                        
	       ░░    ░░░░       
	     ░░  ░   ░░░░▒░     
	   ░░    ░░ ░░  ░░ ░░   
	   ░      ░░░░  ░░  ░   
	  ▒       ░▒▒▒░░░    ▒  
	 ░░       ░▒ ░▒░░░░  ░░ 
	 ░░ ░    ░ ▒▒▒░ ░░   ░▒ 
	 ▒░░     ░ ▒░░░░░░   ░▒ 
	 ▒░░    ░░ ▒░░░░░░  ░▒▒ 
	 ▒▒░  ░░░░░▒▒▒▒░░░  ░▒▒ 
	 ░▒░    ▒▒▒▒ ░▒░░░ ░▒▒░ 
	  ▒░░  ░▒▒▒▒▒▒░ ░░ ░▒▒  
	  ░▒░░░▒▒▒▒▒▒░░░░░░░▒░  
	   ▒▒ ░▒▒░▒░▒░░░░░░▒▒   
	   ░▒▒░░ ░▒░▒▒░░▒░▒▒░   
	   ░▒▒▓▓▒▓▒░░▒▒▒▒▓▒▒░   
	    ░░░▒░░░  ░░░▒░░░    
	                        
	                        
	                        

	Icon (32 x 32):
	                                
	                                
	                                
	                                
	                                
	         ░░         ░░░░        
	      ░░░  ░       ░░░░░░░░     
	     ░░    ░░      ░   ░░░░░    
	    ░       ░░    ░░    ░   ░   
	   ░        ░░    ░          ▒  
	  ░         ░░▒▒▒▒▒ ░░░       ░ 
	  ░   ░      ░░   ░░░▓░       ▒ 
	 ░░  ░      ░ ░░░░▒░░▒░   ░░  ░░
	 ░░░░      ░  ▒▒▒▒░          ░░░
	 ▒░░░      ░  ▒  ▒░         ░ ▒▒
	 ▒░░░     ░░  ▒  ▒░░░░░  ░  ░░▒▒
	 ▒▒░░  ░░░░░░░▒▒▒▒░░░░░░░    ▒▒▒
	 ░▒░░   ░░░░▒▒▒   ▒░░▒░░░   ░▒▒░
	  ▒░░    ░▒▒▒▒▒░░░▒░░▓░░░░ ░░▒▒ 
	  ▒▒░░   ▒▒▒▒▒▒▒▒▒▒░   ░░░░░░▒▒ 
	   ▒░░░░░▒▒▒░▒    ▒░░░░░░░░░▒▒  
	   ░▒░  ▒▒▒▒▒▒    ▒░░░░░░░ ░▒░  
	    ▒▒  ░░░░▒▒░░  ░▒░░░░░░░▒▒   
	    ░▒▒▒░░ ░▒▒▒░░░░▒▒░░▒░▒▓▒░░  
	     ░▒▒▓▓▓▓▓▒░░  ░▒▒▒▒▓▓▓▒▒░░  
	      ░░▒▒▒▒▒░░    ░░▒▒▒▒▒░░    
	          ░            ░░       
	                                
	                                
	                                
	                                
	                                


_NET_FRAME_EXTENTS(CARDINAL) = 0, 0, 0, 0
_NET_WM_OPAQUE_REGION(CARDINAL) = 0, 0, 526, 511
_UNITY_GTK_BORDER_RADIUS(CARDINAL) = 7, 7, 0, 0
_MOTIF_WM_HINTS(_MOTIF_WM_HINTS) = 0x2, 0x0, 0x0, 0x0, 0x0
_NET_WM_ALLOWED_ACTIONS(ATOM) = _NET_WM_ACTION_MOVE, _NET_WM_ACTION_STICK, _NET_WM_ACTION_CLOSE, _NET_WM_ACTION_CHANGE_DESKTOP, _NET_WM_ACTION_ABOVE, _NET_WM_ACTION_BELOW
WM_TRANSIENT_FOR(WINDOW): window id # 0x6c0000f
_NET_WM_WINDOW_TYPE(ATOM) = _NET_WM_WINDOW_TYPE_DIALOG
_NET_WM_SYNC_REQUEST_COUNTER(CARDINAL) = 113247092, 113247093
_NET_WM_USER_TIME(CARDINAL) = 50932690
_NET_WM_USER_TIME_WINDOW(WINDOW): window id # 0x6c00373
WM_CLIENT_LEADER(WINDOW): window id # 0x6c00001
_NET_WM_PID(CARDINAL) = 28784
WM_LOCALE_NAME(STRING) = "en_GB.UTF-8"
WM_CLIENT_MACHINE(STRING) = "luigi-n580gd"
WM_NORMAL_HINTS(WM_SIZE_HINTS):
		program specified minimum size: 526 by 511
		program specified maximum size: 526 by 511
		program specified base size: 0 by 0
		window gravity: NorthWest
WM_PROTOCOLS(ATOM): protocols  WM_DELETE_WINDOW, WM_TAKE_FOCUS, _NET_WM_PING, _NET_WM_SYNC_REQUEST
WM_CLASS(STRING) = "gnome-control-center", "Gnome-control-center"
WM_ICON_NAME(STRING) = "Google account"
_NET_WM_ICON_NAME(UTF8_STRING) = "Google account"
WM_NAME(STRING) = "Google account"
_NET_WM_NAME(UTF8_STRING) = "Google account"