The videos were posted in April, but were only noticed today by Allesebook.de. They are short and weren't shot in very high detail, so there's not much to learn from them that is new.
Update: The videos have been made private. Sorry.
But there are a few details to glean. For example, the videos name the Ultra as the Pocketbook 650, which is probably its model number. The first video also confirms that the Ultra has a rear-facing camera and is reasonably fast at updating the E-ink screen:
According to past leaks, that camera is going to be used to support an OCR function which will enable users to take a picture, convert the image to text, and then edit and save the text on the Ultra.
The leaks have also told us that the Ultra has a 6" Carta E-ink screen with a resolution of 1024 x 758, frontlight, touchscreen, and page turn buttons mounted on the rear of the case. It's supposed to be shipping some time in May, with a retail price of 199 euros.
Of course, Pocketbook hasn't made any official announcements concerning their highly anticipated new ebook reader so the details about the features, price, and release date are still up in the air.
But one detail I can confirm is that the Ultra has the interface which Pocketbook showed us earlier this week: