You can now view and sort long-running Pull Requests from your repository’s
Pull Request page.

When a feature or a bugfix goes on for months but never ships nor dies, we
often want to take a closer look to see what’s preventing that Pull Request
from being shipped or killed. Making it possible to find old but still-active
Pull Requests makes that easier.

Any open Pull Request that has lived for more than a month, but which has
seen activity within the past month, qualifies as long-running. This new
filter displays those long-running Pull Requests sorted by life span: the
amount of time from creation to the most recent activity.