Question

I have heard this term used for managing a code base in GitHub. What does it mean?

Answer 1

As noted within the GitHub docs:

The Fork & Pull Model lets anyone fork an existing repository and push changes to their personal fork without requiring access be granted to the source repository. The changes must then be pulled into the source repository by the project maintainer. This model reduces the amount of friction for new contributors and is popular with open source projects because it allows people to work independently without upfront coordination. […] Pull requests are especially useful in the Fork & Pull Model because they provide a way to notify project maintainers about changes in your fork.