I've been using Magit for a long time, but finally read the manual, and started playing in the deep water. Not sure how to fix what I did...
b Y (Branch / Create from pull request). It asked me for a GitHub id, which seemed strange, but OK, so I entered my email address. Nothing happened, so I tried the command again and it warns me about creating a GitHub API Token.
Presumably I put in the wrong thing for the username. How do I undo this, and how is this command supposed to be used?