When someone sends a PR without a sign-off, I'll apply a label no-dco and also send them a comment pointing them to the contributor guide. Most of the time when I've been helping the OpenFaaS project - people read my message and fix things up without you having to get involved.
derek is a tool in the Tools for GitHub category of a tech stack.
derek is an open source tool with 428 Github Stars and 38 Github Forks. Here’s a link to derek's open source repository on Github
Here’s a list of reasons why companies and developers use derek.