How does GHOSTDAG organize blocks into blue and red lists?

GHOSTDAG sorts every block in the DAG into one of two lists: a blue list for blocks that earn consensus recognition, and a red list for blocks that do not. Blue blocks are tracked alongside a measurement called Anticone size, which the protocol uses when making future classification decisions; red blocks are simply added to the red list without that extra tracking. This two-list structure lets GHOSTDAG keep a full record of every block in the network — including those that arrived too late to lead — while clearly marking which blocks play which role in reaching agreement. For a beginner, this is how Kaspa's network decides which transactions count without discarding the history of blocks that did not win the consensus race.