Early books (from the advent of printing through the 17th century) were generally numbered by leaf instead of by page, meaning when you open the book only the right-side page has a number. The numbering is usually expressed in the same way as manuscript folios, i.e. page number and recto or verso (see https://en.wikipedia.org/wiki/Recto_and_verso). At the moment, it seems like there's no support for this style of numbering in the <pagelist/> function and the numbering has to be entered by hand for each page, like this:
<pagelist 1="1" 2="1v" 3="2" 4="2v" 5="3" 6="3v" ... />
I would like "folio" (and "folioroman") styles be added so we can just mark them like this:
<pagelist from=1 to=50 1to50="folio" />
I have a large number of book scans numbered this way, but I haven't uploaded them yet because there's not an easy way to index them. The few examples I've found in English Wikisource already just discard the page numbers completely and just apply standard pagination.