Add pageBreakSource property

[mattgarrish]

Issue on the EPUB 3 Recommendation

Describe the fix or new feature you propose

The pageBreakSource property was introduced to obsolete the current source-of property. We updated the accessibility techniques to instruct people to use the new property, but we couldn't add it to 3.3.

Now that we're allowed to consider new features, we should look at formally adding it to the package meta vocabulary and update the definition of source-of to point people to this replacement.

[iherman]

I am ok adding this in principle. We may want to have a discussion on the WG first, though, before doing a PR.

CC @shiestyle @wareid

[iherman]

This was discussed during the pmwg meeting on 26 June 2025.

View the transcript

PR 2730 - w3c/epub-specs#2730

<ivan> w3c/epub-specs#2714

wendyreid: adding pagebreak source to the metadata vocabulary property

Hadrien: a general comment, how useful is this?
… in practice I don't see how we can use this if we get an identifier we don't know about
… we can't properly display it. It is hard to make use of this
… in ONIX it is pretty coming to know about the other format of a book
… in a EPUB context I'm not sure what to do with this

CharlesL: this is useful when the end user is creating references to data
… it is more for citing passages by students or scholarly publishing

wendyreid: it doesn't have to be an ISBN, maybe we can be more specific and suggest a URL
… I see your point about this being difficult to display
… maybe this is also a question for the annotations group

mgarrish: the usefulness if for education purposes
… in terms of adding this to the spec. This is trying to address cases
… when a book has no print source
… this is an invitation to make our own standard and no rely on a dc:source
… we can continue working on improving it

wendyreid: is there any opposition to merging this as a step forward?
… alright, cool
… we don't have time for the last one

mgarrish: I'm holding off on this it is bound up in us bumping up the conformance version
… a question of making AccessModeSufficient a must and compatible with the current ISO version
… we may want to wait on this

wendyreid: I will put an "on hold" label on it

<LaurentLM> move to #pm-ann

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