And why is it not described here?
Also, just out of curiosity, when did this come into effect?
The feature was proposed on Meta.SO to allow users to manually award the bounty after the bounty has expired.
I propose a period of 24 hours after the bounty has expired during which the question will not be on the featured tab but the promoter can still manually award the bounty. The "cost" of this would be that no new bounty could be set up until the old one were awarded.
See here for more information on the request and the response by the team.
due to a lot of
whiningvalued community feedback on this issue, I decided it can't hurt to extend the auto-award period 24 hours past the true end of the bounty. So, the question will stop being a bounty question at the original scheduled time but the auto-accept calculations will always occur 24 hours after that.
There's also a blog post on that topic:
To assist forgetful bounty owners, there is a new 24 hour grace period at the end of every bounty. During this grace period, the question will not be featured, but the bounty can still be awarded at any time.