The creator has also provided the following information:
This chest is a Bag of Holding (minor) reward from the Bank Heist at Duskruin Arena. Items stored inside will count only as one item (the container). The current properties of this chest are as follows:
Unique Item Capacity: 1 items -- carrying 0 total items, 0 unique items
Per-Item Capacity: Up to 10 of the same item
Max Encum of Container: 50 pounds (currently carrying 0 pounds)
Despite any messages below, this item cannot be lightened or deepened.
USAGE: DROP/PUT, POKE, PULL (to remove focused item), PUSH, RAISE, RUB, TOUCH, TURN (to set focus on an item to remove).
Important Note: GET will not work with this container.
You get no sense of whether or not the chest may be further lightened.