The xMOON-MOON bridge extension of the ETH-xDai Arbitrary Message Bridge is a pair of mediator contracts allowing the user to transfer xMOON tokens (originally bridged from the Rinkeby testnet) to the Ethereum Mainnet and back.
Anyone who owns xMOON tokens can use the bridge. xMOONs are locked in the bridge contract on the xDai chain and the same amount of MOONs is minted on the Ethereum Mainnet. The reverse operation burns MOONs tokens on the Ethereum Mainnet chain and unlocks xMOONs on the xDai chain.
The main interface to transfer tokens is the OmniBridge UI.