They put an impressive amount of work into that site. There are notifications and an autoupdating counter, and even a livestream. https://www.twitch.tv/reddark_247
Off topic, but giant lists of things are seriously underrated. I’d speculate that a large majority of the sites with a “Recommended for you” section would be much better served by a giant list.
https://webirc.hackint.org/#irc://irc.hackint.org/reddark for a webclient
Not sure why. Maybe I'm missing something about what they chose to display.
edit: I see now, as it clearly says at the top of the page, it’s for subreddits that “are going dark or read-only on June 12th and after”