What is the NFT I received when unstaking GRAM (ex Toncoin)?

When withdrawing GRAM using the Maximum rewards type, Tonstakers processes your request at the end of the current validation part. The staking pool creates a Withdrawal NFT as a confirmation of your pending withdrawal.

Do not send this NFT to other wallets. Unstaking will happen automatically at the end of the current validation cycle.

You can check the status of your withdrawal request at any time in your Tonstakers account.