In the explorer if the contract is an ERC 777 show it in the explorer contract interfaces automatically, just like it does now with ERC-20 and ERC-677
The ERC777 interface can be obtained from open zeppelin https://github.com/OpenZeppelin/openzeppelin-contracts/tree/v2.3.0/contracts/token/ERC777
In the explorer if the contract is an ERC 777 show it in the explorer contract interfaces automatically, just like it does now with ERC-20 and ERC-677
The ERC777 interface can be obtained from open zeppelin https://github.com/OpenZeppelin/openzeppelin-contracts/tree/v2.3.0/contracts/token/ERC777