pub fn load_eth_call_blocking() -> Self {
        Self {
            pre_virtual_blocks: BaseSystemContracts::playground_pre_virtual_blocks(),
            post_virtual_blocks: BaseSystemContracts::playground_post_virtual_blocks(),
            post_virtual_blocks_finish_upgrade_fix:
                BaseSystemContracts::playground_post_virtual_blocks_finish_upgrade_fix(),
            post_boojum: BaseSystemContracts::playground_post_boojum(),
            post_allowlist_removal: BaseSystemContracts::playground_post_allowlist_removal(),
            post_1_4_1: BaseSystemContracts::playground_post_1_4_1(),
            post_1_4_2: BaseSystemContracts::playground_post_1_4_2(),
            vm_1_5_0_small_memory: BaseSystemContracts::playground_1_5_0_small_memory(),
            vm_1_5_0_increased_memory: BaseSystemContracts::playground_post_1_5_0_increased_memory(
            ),
            vm_protocol_defense: BaseSystemContracts::playground_post_protocol_defense(),
            gateway: BaseSystemContracts::playground_gateway(),
            vm_evm_emulator: BaseSystemContracts::playground_evm_emulator(),
            vm_precompiles: BaseSystemContracts::playground_precompiles(),
            _contracts_kind: PhantomData,
        }
    }
Returned system contracts (mainly the bootloader) are tuned to provide better UX (e.g. revert messages).
core/lib/vm_executor/src/oneshot/contracts.rs