GM stands for 'Good Morning' and each is signed by the minter. Feel free to use GMs in any way you want.
These are free to claim from Etherscan (one per address)!
https://etherscan.io/address/0xc467af26314614f0ae0a123f2c7f74ac14037c08#writeContract
VolumeΞ 0
Transactions0
Floor priceΞ 0