From CyborgMatt's Blog:
The contents are currently unknown. The chest’s loot list is referenced as ”international_2013_merch_gift” which suggests that it will be an onsite reward at TI3 for those who purchase merchandise.
“Don’t bother looking for your keys, because this chest doesn’t need one! Free with any purchase for a limited time, our Lucky Lockless Chest contains one of a number of prized possessions that may be found only inside of it. So save your keys for a chest that needs them. You already got lucky!”
PHYSICAL CARD AND FAST CODE! 100% CHANCE FOR MYTHICAL ITEM INSIDE!
Code will be sent ASAP so you can promptly activate it in steam. The code is one time and WILL NOT be activate before being sent to you. The physical card will also be mailed for USA buyers only. (International buyers codes will still be emailed promptly, but must upgrade to expedited delivery if you wish to have physical delivery of the card.) Codes are all unused and in hand. I am attending the 2013 Dota 2 International 3 and was able to get these exclusive cards with the unused digital item codes, from my merchandise purchases at the Secret Shop, setup in the hall in Seattle where the TI3 event is held.
For USA buyers, this comes with the physical card, remember, if you buy this item on the Steam Community Marketplace, you will not get the card, only the code. This listing comes with both for USA buyers. (Intl buyer, for physical card, pay optional fee.)
Code is guaranteed to be unused. Because the item will be spent once you activate the code in your steam account, there are no returns, exchanges or refunds on either the physical card or the product key activation code for the Lockless Luckbox (keyless, unlocked lockbox chest/crate, from the picture item).
CONDITION NOTE: Card will be send in a UltraPro sleeve without the plastic seen in the picture. Card is NOT guaranteed against having cosmetic damage such as bends, dents, or other wear and tear received in shipping, or from handling at the TI3. The cards are all new, but they aren’t the same condition as you would expect from a typical new purchase of playing or trading cards because Valve handles and packs them individually at the event.
The physical card will be mailed only upon request, if you leave a note in buyer comments.
For INTERNATIONAL BUYERS SHIPPING POLICY (outside USA): You will receive your code via email, but the physical card will only be mailed if you upgrade to expedited shipping. You will thereby have the option to save money on shipping by accepting only free electronic delivery.