Basics

The remaining Dune rules should follow Runes’s rules. For the sake of completeness, I will summarize them here (all credits to Casey):

Dune balances are held by UTXOs. A UTXO can contain any amount of any number of dunes.

A transaction contains a protocol message if it contains an output whose script pubkey contains an OP_RETURN followed by a data push of the ASCII uppercase letter D (on Dunes instead of R on Runes). The protocol message is all data pushes after the first.

Dunes input to a transaction with an invalid protocol message are burned. This allows for future upgrades that change how dunes are assigned or created from creating situations where old clients erroneously assign dune balances.

Integers are encoded as prefix varints, where the number of leading ones in a varint determines its length in bytes.