How does this solidity function return the value 4 when I didn’t define any logic in AggregatorV3interface?

 function getVersion() public view returns (uint256) {
        return AggregatorV3Interface(0x694AA1769357215DE4FAC081bf1f309aDC325306).version();
    }

I’m trying to use Aggregator function of chainlink contract but confused bit how it’s working.