Creating a PR with a blank description will "invite" @dwylbot to generate the PR description for you based on your commit messages and referring to the the issues linked to in those commits.

You (the developers) can then edit the PR Description to add/remove any detail.

This will train people to write better commit messages and link to issues as only the commit messages with some detail and a link will be included while others will be flagged as "insufficient detail in commit message".