Pagination source not displayed

[jonaslil]

EPUB Accessibility 1.1 states:

Users need to know the source of the pagination in an EPUB publication to determine whether it will be useful for their needs.
...
When an EPUB publication includes page break markers and/or a page list that correspond to a statically-paginated version of the publication, EPUB creators MUST identify that source in the package document metadata.

For this, the a11y:pageBreakSource property exists.

Recently, support for identifying the pagination source for reflowable EPUBs using this property was added to InDesign.

ONIX provides a related code (13 in Codelist 51) to identify that a digital product corresponds to a specific print edition.

However, neither the Display Guide nor the Techniques mention displaying the pagination source to users.

This raises a question: Why are content creators required to include this metadata, and why do we promote adding support for it in production software, if it is not displayed to users?

[gautierchomel]

I agree with this point; it's important, but "displaying" it may not be the best approach.

Some considerations that I guess lead us not to integrate it before:

• The source is preferably a unique identifier, making it poorly understandable for non-professionals. As a reader, Am I supposed to copy and paste that unique identifier to find the source?
• Early French recommendations had it, but it was not implemented, and booksellers (service providers of bookselling platforms) explained that they use another mechanism to link different versions of a book (prints, audio, digital) so the reader can identify different formats on the same page.
• Some collections we have seen (including Daisy's specialised catalogues) have "print pages" and "source" but no correspondence between both, making the information false.
• Not all metadata are meant to be displayed; some are of better use in BtoB systems

That said, we should include a note or indication that the print pagination source should be identifiable (linked or displayed, depending on the audience).