Reference: https://github.com/solana-labs/solana/blob/f02a78d8fff2dd7297dc6ce6eb5a68a3002f5359/sdk/src/system_instruction.rs#L113-L119.

AuthorizeNonce returns an instruction to change the entity authorized to execute nonce instructions on the account The `Pubkey` parameter identifies the entity to authorize.

Reference: https://github.com/solana-labs/solana/blob/f02a78d8fff2dd7297dc6ce6eb5a68a3002f5359/sdk/src/system_instruction.rs#L58-L72.

GetNonceValueFromAccount returns the nonce value of a nonce account.

InitializeNonce returns an instruction to change the state of an Uninitalized nonce account to Initialized, setting the nonce value The `Pubkey` parameter specifies the entity authorized to execute nonce instruction on the account No signatures are required to execute this instruction, enabling derived nonce account addresses Reference: https://github.com/solana-labs/solana/blob/f02a78d8fff2dd7297dc6ce6eb5a68a3002f5359/sdk/src/system_instruction.rs#L146.

WithdrawNonce returns an instruction to withdraw funds from a nonce account The `uint64` parameter is the lamports to withdraw, which must leave the account balance above the rent exempt reserve or at zero.

RecentBlockhashesSysVar points to the system variable "Recent Blockhashes" Source: https://github.com/solana-labs/solana/blob/f02a78d8fff2dd7297dc6ce6eb5a68a3002f5359/sdk/src/sysvar/recent_blockhashes.rs#L12-L15.

RentSysVar points to the system variable "Rent" Source: https://github.com/solana-labs/solana/blob/f02a78d8fff2dd7297dc6ce6eb5a68a3002f5359/sdk/src/sysvar/rent.rs#L11.

https://explorer.solana.com/address/11111111111111111111111111111111.

https://github.com/solana-labs/solana/blob/da00b39f4f92fb16417bd2d8bd218a04a34527b8/sdk/program/src/nonce/state/current.rs#L8.