Pull requests (PRs for short) are useful as a way to document changes. This provides two benefits:
It provides evidence that this change is indeed useful.
At a later point in the future, a PR can show up as the result of a
git blame. The PR can then retroactively provide context and explain why things are the way they are.
A good PR has the following information:
Title: a short, one-line summary
What is contained in this change?: Describe, in as much detail as useful, what this change does. If the change is visual, consider including screenshots. If the change is visual and interactive, consider including a video.
References: Add links to anything that is relevant for this change, suck as tickets, mockups, and design documents.
Specific things calling out: