specs: Update L2 Output RPC method (#9030)

* specs: Update L2 Output RPC method

* fix per review comments

specs/rollup-node.md

@@ -23,6 +23,11 @@ currently only concerned with the specification of the rollup driver.
 - [Driver](#driver)
   - [Derivation](#derivation)
 - [L2 Output RPC method](#l2-output-rpc-method)
+  - [Structures](#structures)
+    - [BlockID](#blockid)
+    - [L1BlockRef](#l1blockref)
+    - [L2BlockRef](#l2blockref)
+    - [SyncStatus](#syncstatus)
   - [Output Method API](#output-method-api)
 - [Protocol Version tracking](#protocol-version-tracking)
 
@@ -61,6 +66,47 @@ byte hash corresponding to the [L2 output root](./proposals.md#l2-output-commitm
 
 [SSZ]: https://github.com/ethereum/consensus-specs/blob/dev/ssz/simple-serialize.md
 
+### Structures
+
+These define the types used by rollup node API methods.
+The types defined here are extended from the [engine API specs][engine-structures].
+
+#### BlockID
+
+- `hash`: `DATA`, 32 Bytes
+- `number`: `QUANTITY`, 64 Bits
+
+#### L1BlockRef
+
+- `hash`: `DATA`, 32 Bytes
+- `number`: `QUANTITY`, 64 Bits
+- `parentHash`: `DATA`, 32 Bytes
+- `timestamp`: `QUANTITY`, 64 Bits
+
+#### L2BlockRef
+
+- `hash`: `DATA`, 32 Bytes
+- `number`: `QUANTITY`, 64 Bits
+- `parentHash`: `DATA`, 32 Bytes
+- `timestamp`: `QUANTITY`, 64 Bits
+- `l1origin`: `BlockID`
+- `sequenceNumber`: `QUANTITY`, 64 Bits - distance to first block of epoch
+
+#### SyncStatus
+
+Represents a snapshot of the rollup driver.
+
+- `current_l1`: `Object` - instance of [`L1BlockRef`](#l1blockref).
+- `current_l1_finalized`: `Object` - instance of [`L1BlockRef`](#l1blockref).
+- `head_l1`: `Object` - instance of [`L1BlockRef`](#l1blockref).
+- `safe_l1`: `Object` - instance of [`L1BlockRef`](#l1blockref).
+- `finalized_l1`: `Object` - instance of [`L1BlockRef`](#l1blockref).
+- `unsafe_l2`: `Object` - instance of [`L2BlockRef`](#l2blockref).
+- `safe_l2`: `Object` - instance of [`L2BlockRef`](#l2blockref).
+- `finalized_l2`: `Object` - instance of [`L2BlockRef`](#l2blockref).
+- `pending_safe_l2`: `Object` - instance of [`L2BlockRef`](#l2blockref).
+- `queued_unsafe_l2`: `Object` - instance of [`L2BlockRef`](#l2blockref).
+
 ### Output Method API
 
 The input and return types here are as defined by the [engine API specs][engine-structures].
@@ -72,7 +118,11 @@ The input and return types here are as defined by the [engine API specs][engine-
   1. `blockNumber`: `QUANTITY`, 64 bits - L2 integer block number.
 - returns:
   1. `version`: `DATA`, 32 Bytes - the output root version number, beginning with 0.
-  1. `l2OutputRoot`: `DATA`, 32 Bytes - the output root.
+  1. `outputRoot`: `DATA`, 32 Bytes - the output root.
+  1. `blockRef`: `Object` - instance of [`L2BlockRef`](#l2blockref).
+  1. `withdrawalStorageRoot`: 32 bytes - storage root of the `L2toL1MessagePasser` contract.
+  1. `stateRoot`: `DATA`: 32 bytes - the state root.
+  1. `syncStatus`: `Object` - instance of [`SyncStatus`](#syncstatus).
 
 ## Protocol Version tracking