Browser extensions are available to display rating predictions next to each DMOJ scoreboard. You can add the Chrome extension or the Firefox add-on.
TLDR for full extension capabilities:
Without any configuration, this extension will only work for public scoreboard contests.
For hidden scoreboard contests, custom contests are used. You will need to set a request token in the extension options to activate this feature. To sign up for a request token, email [email protected] with the subject "Request Token".
As custom contests are more computationally intensive for the backend, by default, a refresh delay of 10 minutes is in place. If you refresh the contest scoreboard within these 10 minutes, the extension will use the cached response from the server instead of queueing a new custom contest. You can adjust this value in the extension options if you wish.
On the top left of every scoreboard, there is a icon. You can click on this to force refresh rating predictions. For public scoreboard contests, this will refetch the new rating predictions from the standard API. For all other contests (including private contests), this will queue a custom contest.
The source code is licensed under AGPL and is available here.