Think OP means is being able to add a challenge entry as a quest on the tracker. EG, kill xxxxx enemies. Would show, when selected, on quest tracker as

To crush your enemies III
Defeat 0/1000 Enemies.

So you could quick glance at progression of an achievement you are working on instead of having to open the achievement log and locate it.

I'm assuming OP played LOTRO where they had that? XD