It actually says that:
Endless spells and invocations are still in the mix – but instead of spending points to add endless spells when constructing an army, you can pick a manifestation lore. This grants access to a selection of endless spells and invocations that you’ll be able to summon in battle.
Which I understood as endless spells will have their own lore, which you also pick. But do you pick it instead or in addition - yeah, that's the question. I think it's too powerful to pick both and players should opt for one of them. Maybe thematic endless spells will be included in one of the army lores, but who knows.