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