Can someone tell me what the ????? is in the Season of the Wish Triumph?

[Cannon_Fodder]

When I open the Season of the Wish triumph, I see the following options:

Quests
Gear
Riven's Liar
??????? <- what's this?
Secrets

since the start of the season, I see an unread pip for this triumph, but there's nothing to mark as read, so I assume it's something to do with the ??????

Any help here is appreciated.