The 20-byte EVM address of the contract to call. Every contract has an EVM address determined by its shard.realm.num id. This address is as follows:
The first 4 bytes are the big-endian representation of the shard.
The next 8 bytes are the big-endian representation of the realm.
The final 8 bytes are the big-endian representation of the number.
Contracts created via CREATE2 have an additional, primary address that is derived from the EIP-1014 specification, and does not have a simple relation to a shard.realm.num id. (Please do note that CREATE2 contracts can also be referenced by the three-part EVM address described above.)