In that part you can see all clan resources (such as pet essences or clan items for citadel), where they are (in clan trasury) or who has them and quantity. For example If I have 300 chuuga pet essences in my bag, then there appears 300 chuuga pet essence stellar, if there are 300 pet essences in trasury of clan, then appears: 300 chuuga pet essences treasury.
There is another button at the side, that says: return to treasury. Then, the person who has that option active (in ranks from clan) can use that button to move the clan items from bag of any member of clan, to the treasury of clan. That way memebers don't need to be puting each time items in treasury, one person can move from bags and check.
Cheers.