@KevinH: While testing ACE and your plugin, I noticed two more issues that your plugin could check for.
1. If ACE detects empty h1..h6 headings, it'll display the following
minor warnings:
- Element does not have text that is visible to screen readers
- Element's default semantics were not overridden with role="presentation"
- Element's default semantics were not overridden with role="none"
Ideally the plugin should add role=''presentation" attributes to all empty h1..h6 tags. For more information see
this topic.
2. If an epub3 book contains page targets and a pagelist, the metadata section should also contain a dc:source entry with information about the print edition that the page numbers are based on. For more information, see
this topic.
Ideally, the plugin should add a blank dc:source entry with a placeholder text if the nav doc contains a page list and the metadata section doesn't contain a dc:source entry.