Update env description

Author: varasev

setup/env-variables/backend-envs-chain-specific.mdx

@@ -73,7 +73,7 @@ Can be set in format `1h` for 1 hour, `1m` for 1 minute, `1s` or `1` for 1 secon
 
 | Variable                                                      | Description                                                                                                                                                                                                                                                                                                                                                      | Parameters                                                                          |
 | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------- |
-| `INDEXER_BEACON_RPC_URL`                                      | Beacon Chain RPC endpoint used to fetch blob sidecars. Required if `INDEXER_OPTIMISM_L1_BATCH_BLOCKSCOUT_BLOBS_API_URL` is defined and L1 is neither Mainnet, Sepolia, Holesky. Implemented in [#9168](https://github.com/blockscout/blockscout/pull/9168).                                                                                                      | Version: v6.2.0+ <br />Default: `http://localhost:5052` <br />Applications: Indexer |
+| `INDEXER_BEACON_RPC_URL`                                      | Beacon Chain RPC endpoint used to fetch blob sidecars. Required if `INDEXER_OPTIMISM_L1_BATCH_BLOCKSCOUT_BLOBS_API_URL` is defined. Implemented in [#9168](https://github.com/blockscout/blockscout/pull/9168).                                                                                                                                                  | Version: v6.2.0+ <br />Default: `http://localhost:5052` <br />Applications: Indexer |
 | `INDEXER_DISABLE_BEACON_BLOB_FETCHER`                         | If `true` the Beacon data blobs fetcher won't be started, new transaction and block fields will still be extracted. Implemented in [#9168](https://github.com/blockscout/blockscout/pull/9168).                                                                                                                                                                  | Version: v6.2.0+ <br />Default: `false` <br />Applications: Indexer                 |
 | `INDEXER_BEACON_BLOB_FETCHER_SLOT_DURATION`                   | Slot duration in the Beacon Chain in seconds. Implemented in [#9168](https://github.com/blockscout/blockscout/pull/9168). Required if `INDEXER_OPTIMISM_L1_BATCH_BLOCKSCOUT_BLOBS_API_URL` is not empty and L1 is neither Mainnet, Sepolia, Holesky.                                                                                                             | Version: v6.2.0+ <br />Default: `12` <br />Applications: Indexer                    |
 | `INDEXER_BEACON_BLOB_FETCHER_REFERENCE_SLOT`                  | Any past finalized Beacon Chain slot number. Used as reference for blob inclusion slot calculations. Implemented in [#9168](https://github.com/blockscout/blockscout/pull/9168). Required if `INDEXER_OPTIMISM_L1_BATCH_BLOCKSCOUT_BLOBS_API_URL` is not empty and L1 is neither Mainnet, Sepolia, Holesky.                                                      | Version: v6.2.0+ <br />Default: `8000000` <br />Applications: Indexer               |