It depends on the conference; sometimes it's something like "creator of the language shares their vision for the next five years", other times it's "talk from the most famous person we could book", and sometimes just "the talk we liked best from a relatively unknown person". If there are multiple tracks then sometimes the keynote will be the only talk for the timeslot, other times it's not.

Looking at the schedule for this conference, it seems that there's just a single track and all talks are 30 minutes. I wouldn't expect any substantial changes beyond a different timeslot and title.