A pull request (developers say PR) is a proposed change that waits for review before it becomes part of the main work. In GitHub, a PR starts from a branch holding the proposed work and shows the difference from the main version, so reviewers can comment, request changes, approve, or block. The point is to keep any single change from silently becoming everyone’s default.
Picture editing a shared company handbook. You don’t want everyone changing the official version on a whim. You want them to propose the change, show what changed, let someone review it, then decide whether it belongs.
Why you care
The idea started in code, and it applies to any shared work. If one person changes a skill the whole team uses, a PR creates the review point before a bad update repeats across clients. A PR can include checks: tests, a cross-model review where one model reviews another’s work, and a human asking “is this the change we meant?” If two changes collide, the merge conflict becomes visible before the official version changes. A PR is the pause before shared work becomes official.