In the right column on the "questions" page there is a box "Upcoming events" with an entry "Answer the unanswered in 5 days". Where do I find more information on what this event is about? Clicking on it leads to the chat room "TeX, LaTeX, and friends", which seems to be unrelated and is a bit surprising .
There was a time when active community members felt the number of unanswered questions was growing too rapidly. Perhaps the community seemed more inclined to focus on a steady stream of new, answerable questions than to worry and/or deal with questions that may be out-of-scope or lack too much detail.
The result was a scheduled time when everyone can join in and collaborate on sorting out the unanswered pool as best they can. From closing questions as being off-topic, unclear what is being asked (if not reproducible or no minimal example to support a claim) or turning comments into answers. "Answer the Unanswered" is this community event, and it's informally hosted within the regular chat room.