This is "InVideo programming", which is enabled or disabled by the person who uploaded the video. Ideally, it's up to the uploader to make sure that it doesn't obscure text, or become annoying (by default, it shows up only in the last ten seconds, so if it's showing up 44 seconds into a 4-minute video, the uploader has deliberately changed the settings).
It is actually a special type of annotation, so you can make it go away by disabling annotations.