Apparently if you make a really giant linting commit that changes just about every file, GitHub's JavaScript on the Submit PR page will peg the CPU to 90-100+% for a while.
https://github.com/rubysec/ruby-advisory-db/pull/592/commits/bdda9d7be8170ee6ab1e4afff40ebf6c53fd79bb
https://github.com/rubysec/ruby-advisory-db/pull/592/commits/bdda9d7be8170ee6ab1e4afff40ebf6c53fd79bb