See minutes online for a more detailed record of the discussions.
It was agreed on the F2F meeting that the LPF document would not define a significant wording for conformance but will, instead, rely on the WPUB conformance. The proposed text does that, but a stronger reference to ZIP processing may be necessary. Also, there are some issues in relation to the WPUB processing. The final formulation is delayed until the other isssues are solved.
The issue is that the current formulation in the WP document relies on a URL that is the ‘preferred’ address for a WPUB. This requirement does not work for a packaged version of a publication which may not have such ‘preferred address’, though it may have a canonical identification (e.g., an ISBN).
After discussion the current approach is to alleviate the WPUB specification insofar as it should allow a IRI (e.g., a URN) as an identifier value, although the value SHOULD be a URL (i.e., an http address). That would work for packaged publications, too.
This will have to be discussed further; there is now a Pull Request suggesting those changes.