New execution payload global index

pysetup/spec_builders/electra.py

@@ -18,4 +18,5 @@ from eth2spec.deneb import {preset_name} as deneb
             'FINALIZED_ROOT_GINDEX_ELECTRA': 'GeneralizedIndex(169)',
             'CURRENT_SYNC_COMMITTEE_GINDEX_ELECTRA': 'GeneralizedIndex(86)',
             'NEXT_SYNC_COMMITTEE_GINDEX_ELECTRA': 'GeneralizedIndex(87)',
+            'EXECUTION_PAYLOAD_GINDEX': 'GeneralizedIndex(50)',
         }

specs/electra/light-client/sync-protocol.md

@@ -41,6 +41,10 @@ Additional documents describes the impact of the upgrade on certain roles:
 
 ## Constants
 
+| Name | Value |
+| - | - |
+| `EXECUTION_PAYLOAD_GINDEX` | `get_generalized_index(BeaconBlockBody, 'execution_payload_envelope', 'execution_payload')` (= 50) |
+
 ### Frozen constants
 
 Existing `GeneralizedIndex` constants are frozen at their [Altair](../../altair/light-client/sync-protocol.md#constants) values.