Publishing WG Telco, 2019-01-14: Scope of the WG

See minutes online for a more detailed record of the discussions.

Remembering Robin Seaman

Robin Seaman, from Benetech, passed away last week (see a separate obituary). She was a tremendous person, and will be missed. She changed the world by her devotion to accessible publishing. R.I.P.

Scope of the group’s work

As part of the explainer documents it is important to have a clear idea of the scope of the work for the WG for the second half of its chartered time. This was the main topic of the discussion.

A preliminary draft for a scope was put forward by Tzviya Siegman and Ivan Herman (Tzviya has added a section on modularity into the current explainer document, and Ivan’s documented his views as a more detailed proposal in a separate text). The overall approach is:

  • The current WP draft should concentrate on a Web Publication Manifest only (probably with a change in title).
  • The work on audio books should be in a separate, Rec-track document as its own profile, and is the main subject of work for 2019.
  • A document on packaging should be developed, aimed at Web Publications in general (the format to be decided soon).
  • The group may/should also look at other profiles as they come up (visual narrative, scholarly, educational) but not as a Rec track in this charter period.
  • The section on affordances of the current draft should migrate into either a separate Note or merged with the UCR Note

Other profiles, adoption of Web Packaging, etc, would be the subject of a possible rechartered group in 2020.

There was an overall agreement with this line of scope and work, and it was agreed that the scoping statements would be merged/added with the explainer; this is important for a TAG review of the group’s work.

There were also some further discussions on whether it is important/possible to re-base the work on the manifest on an abstract data model (Dave Cramer has written a first draft). The discussions were not fully conclusive, but a data model part may become the subject of a separate Note or be incorporated into the document on Web Publication Manifest.

Publishing WG Telco, 2019-01-07: Packaging for audio

See minutes online for a more detailed record of the discussions.

There was only one topic for discussion on the call: continue the discussion on the packaging format for Web Publications in general, but with a particular focus on audio books; this was a followup of the Audio Task Force meeting in December.

As a result of that audio task force meeting a draft has been created for “OCF Lite” (temporary name). The idea was to take the EPUB 3 OCF document as a starting point, and adapt it to the WP/Audiobook needs. The approach was to remove the EPUB3 specific requirements and files, add some WP specific ones (e.g., adding a Primary Entry page in HTML, a manifest in JSON). There is a separate comment listing the main differences in the relevant github entry.

A number of issues were discussed during the call. Some main ones:

  • Whether the removal of the manifest file is a good idea or not
  • Relationship to the “original” EPUB 3 OCF file, ie, whether the document should simply refer to it and list the differences only or be a standalone document
  • Relationship to the Web Packaging Work at W3C/IETF. This is actually the most important issue; some of the comments on the call:
    • The Web Packaging spec is more “Webby”, and would solve a number of issues like security, origin, etc. However, the specification is not yet there, and it may take longer than the audiobook community can wait to get it finalized, standardized, with a relevant tools being available, etc. The audiobook spec needs a packaging approach now.
    • It would be a hard sell to ask audiobook publishers to produce HTTPS request/response pairs, turn the results into CBOR, etc, when they just want to combine a bunch of MP3 files into a file. Web Packaging may be an overkill…
    • There may be a need for several packaging formats, depending on the circumstances, media, use cases.

There may be other packaging formats out there (e.g., HEIF), though, so due diligence requires looking at those, too, before making a final decision. A separate github issue has been setup, with a life-span of two weeks, to look at this and, possibly, a final decision will be made then.

Publishing WG Telco, 2018-12-17: vanilla browser, explainer

See minutes online for a more detailed record of the discussions.

Entry page and the vanilla browser

The question that was discussed was “can a primary entry page be opened in a vanilla browser” and what can be expected. The question was later modified to “Is it possible to open the entry page in any standards-compliant user agent that is not WP-aware (henceforth “minimal browser”)”. While the question sounds like a tautology—since the entry page is html, it can be opened in a browser—the real issue was whether that page is “meaningful”. That raises questions like:

  • are we talking about a fully declarative publication only or a publication with a (albeit possibly minimal) polyfill (or equivalent)?
  • is it required to provide a ToC in the primary entry page, or can the user, potentially create a completely empty page?

There has been no formal resolution on the call.

WP Explainer

Dave Cramer has produced a draft for a “WP Explainer” for a very high level overview of what the WPUB work is where it goes today. The goal is to, sometimes after the holidays, submit this to a general TAG review. The discussion focused on some possible improvements:

  • spell out things that, though obvious for the publishing community, may not be for “outsiders” (e.g., role of ToC)
  • talk about the expectation (and non-expectation) v.a.v. browser engines (e.g., that the community may have to develop its own extensions and not expect browser engines to do everything)
  • the role and influence of EPUB in the design
  • etc.

The explainer will be updated based on these comments.

Publishing WG Telco, 2018-12-10: Audiobook issues

See minutes online for a more detailed record of the discussions.

The meeting fully centered around issues related to the audiobook discussion

Editorial structure for WP and Audiobooks

The practical issue that has to be solved is whether the audiobook represent a separate document (specification) with its own set of editors and a separate repository. There was no consensus yet on this:

  • Some worried that having a separate document and repo may raise the difficulties for a newcomer to join the discussion and to have an overall view; managing the issues over several repositories also create challenges.
  • It is unclear whether having everything in one document scales. What if we get new modules, like educational books or mangas?
  • On the other hand, everything in one big document may also make things unreadable (and difficult to manage by editors).

To be followed up.


(Issue #352)

Audiobooks need some form of packaging for immediate deployment. Because Web Packaging is not available yet, one possibility may be to go for OCF like for EPUB. However, there are number of technical and practical issues:

  • OCF is an ISO standard, which makes it usable and referenceable, but what we would need in fact is an “OCF Lite”: dropping some features like the order requirements as used in EPUB. That makes it more complicated.
  • Are we talking about packaging for audio books or for WPUB in general? What are exactly the borderlines between what is audiobook specific and what is generic WP?

There was also a proposal that, in the case of a packaged audiobook the required, HTML primary entry point would be dropped from the audiobook. However, that would mean a packaged audiobook is not round trippable any more: if unpacked, it is not a Web Publication. This was raised as a problematic issue as well.


(Issue #351)

At the moment it is possible to add an Audiobook type to the manifest for, well, audio books. There may be other types coming (e.g., for mangas) for which there is not yet a corresponding type in The question is whether it is possible to add our own type; if yes, how, and what does it exactly mean for user agents.

The answer to the first question turns out to be ‘yes’. As discussed at TPAC with DanBri, we can add such a type to, say, WikiData, and that works potentially well with We are talking about 5-6 additional types, not more. However, we have to be careful about not getting to the analogous situation as “this feature is working best with X browser”. User agents should be able to do something sensible with all publications, even with that specific type set.

Publishing WG Telco, 2018-12-03: MVP

Publishing WG Telco, 2018-12-03: MVP

See minutes online for a more detailed record of the discussions.

A discussion about Minimum Viable Product, as documented in the UCR led to a debate about where accessibility requirements should fall. Some of the accessibility experts in PWG agreed to work with the UCR team to clean up the accessibility requirements and make sure they are assigned to appropriate classification.

The WG worked through closing issues with the propose-closing label.

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Publishing WG Telco, 2018-11-26: TOC

See minutes online for a more detailed record of the discussions.

The meeting was fully on the issue of Table of Contents (a.k.a. TOC), which is the subject of two different issues: #291 and #350. These two issues have been open for a very long time.

The agenda of the call includes a short explainer (at the end of the mail) on where the discussion has gone over the months, and what are the open issues. Two of the questions, listed in the explainer, have been resolved, namely:

Is there a need to define, and make accessible from the manifest, an HTML-based structured TOC, usable to extract a simple hierarchical data structures containing labels and links?

The resolution accepted at the call is:

The WP manifest will have a reference to a machine-readable TOC, the draft will have to define the HTML structure for it. The TOC is recommended. There should be documentation in the spec on how that TOC is to be used by Reading Systems and Authors.

The “machine-readable HTML structure” structure, at first, will be based on the EPUB Navigation Document Specification though it may still evolve.

The second question was:

Is there a need to make accessible from the manifest the reference to a visual TOC, without any restriction on what that reference would contain?

The resolution at the call:

Close issue #350, possibly replace it with a more general notion of landmarks.

The third question, namely

Is there a need to allow the author to express the (structured) TOC directly in the manifest as a data structure in JSON?

was not discussed due to time; the agreement is that these open issues will be closed, and a new issue will be opened concentrating on this question only.

Publishing WG Telco, 2018-11-19: Use cases, Minimal Viable Product

See minutes online for a more detailed record of the discussions.

UCR and “Minimal Viable Product”

The UCR has been reorganized: an explicit UC for TOC has been added, and the list of requirements contains now “classes of conformance” (the term is not final) to categorize possible implementations.

The “minimal” category is in line with what the group referred to as “Minimal Viable Product” or “Minimal Viable WPUB” at the F2F meeting in Lyon, ie, to define what is the minimal set of feature that a WPUB User Agent is expected to do. The group spent therefore the time going through the “minimal” table to see whether the list does (does not) correspond to an MVP. (Actually, the list discussed at the call was an earlier version, the editor‘s draft already reflects some of the changes.) This discussion was the first step towards such an MVP specification, to be done in the coming weeks.

F2F dates

A proposal for a F2F meeting was made for the 6-7 May, 2019, in Cambridge, MA, USA, hosted in the Kendall Square offices of Google.

Publishing WG Telco, 2018-11-12: Origin, TOC

See minutes online for a more detailed record of the discussions.


The question on “origin” came up in the discussions and issues (e.g., #321) in the past. Daniel Weck gave an overview (completed by Leonard Rosenthol) of what “origin” means in the context of the Web and what effect it may have on our specifications. It is closely related to the security issues and model on the Web. It does raise questions like “does the manifest have to be same origin as entry page?” or “if WP is just a collection of stuff that are glued together with a manifest, then it leaves open the possibility of someone creating a publication without my consent.” A typical issue may be whether the group should consider whether some pieces MUST be same origin.

The discussion did not draw a final conclusion on what of the origin issue should be reflected in the (normative) part of a standard, and what should be more in a possible document on deployment and implementation choices. It is also a question whether any restriction should be made based on today’s security model, which may cause problems in the future. A smaller group will explore the problem area further.

Note the related issue 104 around browsing contexts, that is still open.


There is a long standing issue on TOC; one of the aspect of that issue is what type of prescribed HTML structure is useful and realistic to provide a framework for an HTML based TOC. Juan Corona made an online demo of an algorithm he was looking at (available on github) exploring the space. It seems that a more general HTML structure may be defined for a TOC, though it does need further work to specify it.

Possible F2F dates

A proposal for a F2F meeting was made for the 6-7 May, 2019, in Cambridge, MA, USA, hosted in the Kendall Square offices of Google. To be decided.

Publishing WG Telco, 2018-11-05: TPAC memories, possible rechartering, use cases

See minutes online for a more detailed record of the discussions.


Wendy Reid wrote a nice blog post on TPAC summarizing the two days and the main outcomes.

Possible Rechartering

One of the pending issues (to be decided by the Business Group) is whether the WG would take up a standardization track for EPUB 3.2. If this indeed happens, the group will have to re-charter. The details of what Rec track would mean for EPUB 3.2 (testing methodology, tests, etc) will be the subject of discussions within the EPUB 3.2 CG, whose results should be brought into the WG if successfully recharter.

Rechartering would also include re-thinking the work on WPUB and related specs. One possible approach is to “modularize”, having a slimmer document on the Web Publication Manifest, and dedicated standards for specific areas. Audiobooks is the first, comics, scholarly publishing, etc, may come later. Packaging may have to be delayed for the general case (though may be defined specifically for dedicated standards) hoping for the Web Packaging work to come to the fore. Decision must be taken on EPUB 4 (the messaging might be tricky with EPUB 3.2 also ongoing).

The details will have to be made in a new charter, to be drafted first by the Publ. champion, WG chairs, staff, and then publicly discussed before voting begins. The TAG’s opinion may have to be sollicited, the role of the separate Publishing CG should be clarified (as a source of possible new technologies). This process will take several months…

Use Cases

The new version of the UCR makes the bridges between the use case requirements and the current text. There is a good match, and there are only 5 requirements that may not have a direct counterpart in the WP draft.

The work should continue in using these bounds to come up with a clear statements on affordances, ie, answering to the question “what should the User Agents do?”.

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