Tracing a mysterious GitHub webhook

A little while ago, as I was wrapping up my day, I discovered an active webhook configured in the digiusher code repository. Events including PRs, issues, and commits were being sent to this webhook. I make it a habit to sweep our authorized apps on GitHub occasionally but I had never paid attention to webhooks for some reason. It didn’t help that this webhook was configured not at the organization level but on an individual repository.