Additional note from Redon -
Before you start criticizing the chapter, this time I really recommend you to wait for the images/scans. The fight between Luffy and Kaidou is visually amazing, the chapter gains a lot with images.
Regarding the devil fruit that the Gorousei talk about, as you have seen in the summary, this chapter does not say which one it is.
As a reference, I can tell you that the final sentence of the Gorousei ("The reason is that they wanted to eliminate the original name of that fruit from history!?") appears in the final vignette of the chapter, in which we see Zunesha just behind the fleet of ships of the World Government (the one I was talking about the other day). Although it's not clear to me if Oda wants to tell us whether the devil fruit is linked to Zunesha or not.
My opinion is that I think the Gorousei is talking about the devil fruit of one of the users Wano right now, but I couldn't tell if they are talking about the Gomu Gomu no Mi or a different fruit. I also think the Gorousei don't have much idea on what the World Government did in the past on this topic (the Government or a Gorousei from previous generations).