[His eyes flicker down at the movement, and then back up to her. A candid confession of ulterior motives from Hermione does not inspire distrust. Rather, he is curious, and leans closer to her, interested in what she has to present to him.]

Very little, in truth. I know they are not functioning now. I know their basis is magic. I . . . suspect they are used in manners not overtly disclosed to us. [Spying. He means they're used for spying by the Monarchs. But he isn't going to say it in the heart of Caer Glaem.] What of them?