"My dear Professor, surely a sensible person like yourself can call him by his name? All this 'You-Know-Who' nonsense - for eleven years I have been trying to persuade people to call him by his proper name: Voldemort." Professor McGonagall flinched, but Dumbledore, who was unsticking two lemon drops, seemed not to notice. "It all gets so confusing if we keep saying 'You-Know-Who.' I have never seen any reason to be frightened of saying Voldemort's name. (Harry Potter and the Sorcerer's Stone)
It seems ‘all this ‘You-Know-Who’ nonsense’ make a main clause in the semantic aspect, and for-clause subordinate one showing the reason for the main clause. But there’s no verb in the seeming-main clause. What do we call this kind of clause or phrase? Is there just omitting of verb? Or can a noun phrase make a clause semantically like an absolute phrase?