

It’s a joke. They are pretending they can’t remember the very obvious/absurd/silly/etc thing, so they have to check their notes before finishing the thought.
I think it might have its origin in courtroom dramas having prosecutors being catty with the defense but that’s just a barely informed guess tbh
It went from punk/alt rock/grunge to hip hop to synth pop for me, with speckles of all sorts of folk and electronic throughout. MagBay is my current favorite, and my first was Nirvana.