I triggered an update via Discover, and I think I clicked the [x] (close) title bar button a little too quickly. Would that have stopped the update in mid update or does Discover do the update in a subprocess that continues even if Discover is closed?
depends if it was close to tray or killed the process but no you didn’t break it by closing it even if you did kill the process. the package manager behind discover will just repair the package and move on. Package management is a lot more robust than something like windows update.