Episode - https://laracasts.com/series/how-to-contribute-to-open-source/episodes/9
The structure of the PR description is:
intro
short video of the feature in action
purpose
why the new feature is relevant
how it can be used
usage with code samples
basic example
advanced examples (how to revert a step) taken directly from the tests code
wrap-up
with thanks to the maintainers of the package - classy