To the winner of the giveaway: the key is from Humble Choice August 2024 but when a I try to reveal it I instead receive the message "Keys are temporarily exhausted for this product. As soon as we receive more keys, we will add them to this page and send you an email.".
I didn't know keys were exhausted until after the end of the giveaway and Humble support told me they can't give an estimate on how long it'll take to restock the keys. If you are willing to wait, I promise I'll add the key as soon as I receive it.