The Modern Forgery Hypothesis

[Mauro]

One case that stands out is the anomaly, and possible (to me probable) gross anachronism of the use of foldouts in the Voynich. There simply is no other example from the time revealed by the C14 tests. Yes, "accordion type" prayer books, .... (omissis, but interesting reading)

The foldouts are a double-edged sword for the modern forgery theory (MFT). They can be seen as a 'gross anachronism' where, consequently, Voynich (a master forgerer according to MFT) made a gross revealing error (and for no discernible purpose I can think of, why add foldouts in the first place?), or as someone who long ago thought he really needed some more space for all those cool diagrams he had in mind and used some of the low quality  parchment he had to add the foldouts (mores of the times notwithstanding).

Reasoning a fortiori in favor of MFT I can't really give more than even 1:1 odds to the two possibilities, which changes nothing for MFT nor for the ancient manuscript theory, so for me the evidence from the foldouts is at best (for MFT) irrelevant. But not reasoning a fortiori I'd give at least 1:3 against "Voynich the forgerer made a purposeless gross mistake", which is a (quite weak, by itself) evidence against MFT.