📄️ Version
Introducing the block version number field.
📄️ Previous Block
Introducing the Previous Block field in the block header.
📄️ Merkle Root
Introducing the concept of the Merkle root.
📄️ Time
Introducing the timestamp in the block header.
📄️ Bits
Introducing the difficulty bits representing the difficulty target of a block.
📄️ Block Hash
Introducing how the block ID is calculated.
📄️ Nonce
Introducing the nonce field in the block header.
📄️ blk.dat
Introducing the storage format of Bitcoin block files blk.dat.