add updates to execution payload for extended header under EIP-7742

Author: ralexstokes

src/engine/prague.md

@@ -10,6 +10,7 @@ This specification is based on and extends [Engine API - Cancun](./cancun.md) sp
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
 
 - [Structures](#structures)
+  - [ExecutionPayloadV4](#executionpayloadv4)
   - [PayloadAttributesV4](#payloadattributesv4)
 - [Methods](#methods)
   - [engine_newPayloadV4](#engine_newpayloadv4)
@@ -30,6 +31,29 @@ This specification is based on and extends [Engine API - Cancun](./cancun.md) sp
 
 ## Structures
 
+### ExecutionPayloadV4
+
+This structure has the syntax of [`ExecutionPayloadV3`](./cancun.md#executionpayloadv3) and appends the new field(s): `targetBlobsPerBlock`.
+
+- `parentHash`: `DATA`, 32 Bytes
+- `feeRecipient`:  `DATA`, 20 Bytes
+- `stateRoot`: `DATA`, 32 Bytes
+- `receiptsRoot`: `DATA`, 32 Bytes
+- `logsBloom`: `DATA`, 256 Bytes
+- `prevRandao`: `DATA`, 32 Bytes
+- `blockNumber`: `QUANTITY`, 64 Bits
+- `gasLimit`: `QUANTITY`, 64 Bits
+- `gasUsed`: `QUANTITY`, 64 Bits
+- `timestamp`: `QUANTITY`, 64 Bits
+- `extraData`: `DATA`, 0 to 32 Bytes
+- `baseFeePerGas`: `QUANTITY`, 256 Bits
+- `blockHash`: `DATA`, 32 Bytes
+- `transactions`: `Array of DATA` - Array of transaction objects, each object is a byte list (`DATA`) representing `TransactionType || TransactionPayload` or `LegacyTransaction` as defined in [EIP-2718](https://eips.ethereum.org/EIPS/eip-2718)
+- `withdrawals`: `Array of WithdrawalV1` - Array of withdrawals, each object is an `OBJECT` containing the fields of a `WithdrawalV1` structure.
+- `blobGasUsed`: `QUANTITY`, 64 Bits
+- `excessBlobGas`: `QUANTITY`, 64 Bits
+- `targetBlobsPerBlock`: `QUANTITY`, 64 Bits
+
 ### PayloadAttributesV4
 
 This structure has the syntax of [`PayloadAttributesV3`](./cancun.md#payloadattributesv3) and appends the fields: `targetBlobsPerBlock`, `maxBlobsPerBlock`.
@@ -52,7 +76,7 @@ Method parameter list is extended with `executionRequests`.
 
 * method: `engine_newPayloadV4`
 * params:
-  1. `executionPayload`: [`ExecutionPayloadV3`](./cancun.md#executionpayloadv3).
+  1. `executionPayload`: [`ExecutionPayloadV4`](#ExecutionPayloadV4).
   2. `expectedBlobVersionedHashes`: `Array of DATA`, 32 Bytes - Array of expected blob versioned hashes to validate.
   3. `parentBeaconBlockRoot`: `DATA`, 32 Bytes - Root of the parent beacon block.
   4. `executionRequests`: `Array of DATA` - List of execution layer triggered requests. Each list element is a `requests` byte array as defined by [EIP-7685](https://eips.ethereum.org/EIPS/eip-7685). The first byte of each element is the `request_type` and the remaining bytes are the `request_data`. Elements of the list **MUST** be ordered by `request_type` in ascending order. Elements with empty `request_data` **MUST** be excluded from the list.
@@ -107,7 +131,7 @@ The response of this method is extended with the `executionRequests` field.
 #### Response
 
 * result: `object`
-  - `executionPayload`: [`ExecutionPayloadV3`](./cancun.md#executionpayloadv3)
+  - `executionPayload`: [`ExecutionPayloadV4`](#ExecutionPayloadv4)
   - `blockValue` : `QUANTITY`, 256 Bits - The expected value to be received by the `feeRecipient` in wei
   - `blobsBundle`: [`BlobsBundleV1`](#BlobsBundleV1) - Bundle with data corresponding to blob transactions included into `executionPayload`
   - `shouldOverrideBuilder` : `BOOLEAN` - Suggestion from the execution layer to use this `executionPayload` instead of an externally provided one