They describe a leaderboard built from server members' shared gaming activity, while actual rollout remains unconfirmed.
When It Appears
“Who has played on the most days?” can appear on a server view that ranks shared gaming activity and shows a timed competition when Discord displays the competition question ranking who played on the most separate days.
When “Who has played on the most days?” is shown, the current step is presenting the competition question ranking who played on the most separate days.
Search Intent
A user who saw “Who has played on the most days?” in Discord is likely searching to confirm that it means the competition question ranking who played on the most separate days, where it appears, and which state it describes.