The white text is part of the chyron? Would the black print also be something that a chyron would do? And the X?
If you look carefully at Political Teen's video clip, especially if you step through it frame by frame, you will see the the appearance and disappearance of the black X corresponds exactly with two successive updates of the crawler text at the bottom. I also notice that the black X fades in and fades out, which is exactly what happens to the crawler text as it is updated. They do this so the text appears to move more smoothly, rather than jerking across the screen.
So, this tells me whatever equipment they use to generate the crawler is also the equipment that generated the black X. I have to assume that this eqipment has control of the whole screen, not just a strip at the bottom. Parameters like text size, color, font, postion, speed of crawl, and so forth should all be programmable. Somebody at CNN has the job of feeding new material into the crawler. That person is probably having a conversation with his or her boss this morning.