Unused accounts
The finalize_block instruction includes a redundant payer account that
incurs no fees (since there is no account creation in the instruction), and
serves no access-control purpose (since the instruction is permissionless).
As such, the payer account can be removed to simplify the interface and reduce potential confusion about its purpose.
This issue has been acknowledged by Layer N, and a fix was implemented in commit 72f1cbed↗.