Between the lines the spec suggests that finding the ToC follows these steps:

1. If the PEP is used (see The fragile position of the Primary Entry Page #61 on this, b.t.w.) and the PEP does include a ToC (i.e., an element with role=doc-toc) then take this
2. Otherwise, use the manifest to locate, as part of one of the Linked Resources, a reference to the ToC (following Pub Manifest §4.8.1.3 and then Pub Manifest §C.3).

However, (1) is not clearly specified in the document. The document(s) today would require to add a linked resource into the manifest pointing at the PEP...

I believe that:

• just as we do with the manifest processing in Audiobook §6, there should be a separate section on how this profile extends the general text
• again just as in the manifest processing part there should be an 'extension point' defined in Pub Manifest §C.3 for profiles in general.