I clicked a magnet link and Chrome gave me the popup saying "This site is trying to open an external app." I clicked the checkbox for it to never ask me again but I accidentally clicked the "Do Nothing" button. Now I can't seem to revert that decision.
As per this question, if I go to Settings > Content Settings (under Privacy) > "Manage Handlers..." nothing is listed. Right clicking a magnet link does not provide an "Open Link With..." option either. The question seems to be outdated.