Threat from Good Rolls?

Simple question: If a GM is rolling for an NPC and gets extra successes, do those extra successes translate into Threat and placed into the Threat pool? Or maybe extra successes count effectively like bonus momentum that needs to be spent right away on that task? Or maybe no Threat is generated whatsoever, regardless of how good the roll is?

I maybe missed something in the rules, but this question eludes me.

Does the GM gain Threat from good roles of their NPC?
Basically: Yes.

Technically: No.

Just like PC, NPC do get Momentum from good rolls. So technically they don’t get threat.
But according to p281 of the Core Rules (cf. the fourth bullet point) they can spend this Momentum to generate threat. So extra successes in fact are bonus Momentum that can be spent right away on that task (e.g. for bonus questions). With the extra option to transform them into Threat.

In my opinion, there is no basically about this. It is simply a flat yes. In multiple places within the core book (page 281, 291, to name two specific pages) it states that NPCs utilize the GM threat pool for their actions. This is anything from buying extra dice for the roll, to buying advantages and complications.

Supporting characters and any character controlled by the players use the player’s Momentum Pool. Every other character uses the GM threat pool, regardless of if they are an ally or adversary. Yes, you can use momentum gained in a dice roll immediately for bonus ‘questions’, advantages, anything that you may consider ‘bonus’ momentum for, or convert them on a 1 for 1 to threat.