Add the ability to check the time and date when a challenge link was completed. This would be helpful for challenges that have a deadline and filtering out results that were completed after the deadline. One implementation could be by simply hovering over the final score of a player or any other element in the row to show this info, similar to how profile creation date used to be displayed.

To take this a step further, a deadline could be added when setting up a challenge link, which would close a challenge and prevent any further scores from being added to the leaderboard. After the deadline, players who have not played the challenge could either play the challenge for fun (and not add their score to the leaderboard) or simply see the results.