What follows when a crypto platform, protocol or project is fully operational and migrates to a different blockchain.
A mainnet swap is the mass movement of traders from one blockchain network to another due to the maturing of their crypto protocol. This usually occurs when the protocol is fully functional and a native blockchain network has been formulated that can now accommodate the protocol and its users. Thus, the swap consists of users replacing their cryptos (from the old network) with newly-issued alternatives using a predetermined ratio.
Mainnet swaps are not unusual. Few crypto projects are launched with a new blockchain network. The development team typically relies on others until they can develop their native network for their users.