EIP-7658: Light client data backfill

[etan-status]

Discussion thread for Add EIP: Light client data backfill by etan-status · Pull Request #8341 · ethereum/EIPs · GitHub

Related notes:

• Enable light client data backfill by tracking best `SyncAggregate` by etan-status · Pull Request #3614 · ethereum/consensus-specs · GitHub
• Light client roadmap for Electra - HackMD
• Light Clients Breakout Room - March 6, 2024 - HackMD