The new illustration has removed the old h1 h2 F3 notation. This should be removed from the specification - probably only in StripCell
StripCell makes reference to FrontOverfold and BackOverfold - only overfold is shown.
SignatureCell has no reference to Overfold at all. Missing from SignatureCell?
Table 8.267: StripCellParams Element
|BackOverfold ?||...||(F3) Value for the overfold at the back side.|
<and all other rows>
Figure 8-55: Definition of margins in StripCellParams
Note: Overfold in this figure refers to one of @FrontOverfold or @BackOverfold depending on whether the page is on the front half (in front of the middle fold) or the back half (in back of the middle fold) of the signature.