$ xwininfo -tree -root| grep "has no name"
0xa800048 (has no name): () 390x43+944+621 +944+621
0xa80142e (has no name): () 147x26+1056+66 +1056+66
0xa80007a (has no name): () 156x26+1275+356 +1275+356
0x40000e (has no name): () 1920x22+0+-22 +0+-22
0x40000d (has no name): () 1920x22+0+0 +0+0
0x1800008 (has no name): () 1x1+-1+-1 +-1+-1
0xa801454 (has no name): () 409x215+1006+773 +1006+773
0x980000f (has no name): () 1x1+-1+-1 +-1+-1
0xa80138d (has no name): () 140x26+707+837 +707+837
0xb000001 (has no name): () 1x1+0+0 +0+0
0xa800005 (has no name): () 1x1+0+0 +0+0
0x9200004 (has no name): () 1x1+0+0 +0+0
0x8e00001 (has no name): () 1x1+0+0 +0+0
0x9000004 (has no name): () 1x1+0+0 +0+0
0x8400004 (has no name): () 1x1+0+0 +0+0
0x800001 (has no name): () 10x10+-20+-20 +-20+-20