It"s used to select items with keyboard shortcuts.
From the help menu:

k Move Up When on a list, move the cursor up
j Move Down When on a list, move the cursor down
i Select Item When on a list, select an item

The arrows positions signals the item which is selected is you press 'i'.

Thanks relevart!

Using keyboard shortcuts to manipulate your tasks can speed up some tasks tremendously. You can find a complete list of keyboard shortcuts here.

Hope that helps!

Thanks... I could not figure that one out!