Some of the responses are a little over broad. Sometimes in an interview the discussion will revolve around current projects and challenges and the candidate needs to pay close attention and repeat back. Thats really all there is to it.
It wasn't in the bland HR generated job req but todays task is we're trying to talk to the MQTT server and ... anyway five minutes later to see if the candidate is listening the interviewer asks why you ... If the candidate responds with something indicating the candidate heard the interviewer five minutes ago talk about MQTT servers or libraries or whatever, then awesome, thats exactly what the interviewer expected. If the candidate rambles about their resume its because they were not paying attention and in the workplace its annoying to tell someone what to do and then have them go off on a totally separate tangent. If the candidate panics and goes lost in space, they were daydreaming about lunch or the TV show they watched last night and that is also annoying in a professional workplace during a professional conversation.
"Yo I heard you say in this interview you're working on X Y and Z right now and let me tell you all about how I can speed it up and lower risk by helping you out with X Y and Z."
Oh and don't surprise the interviewer. They read your resume and expect an answer along the lines of what they read. Or heard. Even if its true don't suddenly shout out Holy Cow thats exactly like a programming assignment I did in class or some random thing. Before they even asked they already guessed what your response will be and you want them all warm and fuzzy by restating what they expect.
You know take home projects? This question is like a take home project without the take home. You mention rabbitmq they freak out or go on a fizzbuzz tangent or talk about freebsd in general, not so good. If it were a take home assignment they'd fail or come back with a solution to a different problem, not so good. You mention rabbitmq and they respond rabbitmq ah now there's an attentive on task future employee whom if I HAD assigned a rabbitmq take home project would probably have returned with a solution to the rabbitmq problem as opposed to something else or nothing...
Edited to add, think of it like the conversation you probably have with your boss on a regular basis. Especially if the interviewer might be your new boss. Boss says yo I'm getting a lot of heat about bug #15133 and feature request #126699 and then you talk about the weather for ten minutes and the conversation closes with some sort of what you're doing today? and it better revolve around #15133 and #126699 and I totally have a plan and the skills to handle it, definitely not oh shit I type meta-x panic-mode, or I have no idea, or how about that TV show last night, or whatever.