Improve comments in the contract's code.

contracts/0.4.24/nos/NodeOperatorsRegistry.sol

@@ -102,7 +102,7 @@ contract NodeOperatorsRegistry is AragonApp, Versioned {
     uint8 internal constant TOTAL_DEPOSITED_KEYS_COUNT_OFFSET = 3;
 
     // TargetValidatorsStats
-    /// @dev Target limit mode, allows limiting target active validators count for operator (0 = disabled, 1 = soft mode, 2 = forced mode)
+    /// @dev Target limit mode, allows limiting target active validators count for operator (0 = disabled, 1 = soft mode, 2 = boosted mode)
     uint8 internal constant TARGET_LIMIT_MODE_OFFSET = 0;
     /// @dev relative target active validators limit for operator, set by DAO
     /// @notice used to check how many keys should go to exit, 0 - means all deposited keys would be exited
@@ -689,7 +689,7 @@ contract NodeOperatorsRegistry is AragonApp, Versioned {
 
     /// @notice Updates the limit of the validators that can be used for deposit by DAO
     /// @param _nodeOperatorId Id of the node operator
-    /// @param _targetLimitMode target limit mode (0 = disabled, 1 = soft mode, 2 = forced mode)
+    /// @param _targetLimitMode target limit mode (0 = disabled, 1 = soft mode, 2 = boosted mode)
     /// @param _targetLimit Target limit of the node operator
     function updateTargetValidatorsLimits(uint256 _nodeOperatorId, uint256 _targetLimitMode, uint256 _targetLimit) public {
         _onlyExistedNodeOperator(_nodeOperatorId);

contracts/0.8.9/DepositSecurityModule.sol

@@ -32,6 +32,11 @@ interface IStakingRouter {
 /**
  * @title DepositSecurityModule
  * @dev The contract represents a security module for handling deposits.
+ *
+ * The contract allows pausing deposits in response to potential security incidents and
+ * requires a quorum of guardians to authorize deposit operations. It also provides a mechanism
+ * to unvet signing keys (a vetted key is a validator key approved for receiving ether deposits)
+ * in case of any issues.
  */
 contract DepositSecurityModule {
     /**
@@ -579,20 +584,7 @@ contract DepositSecurityModule {
         bytes calldata vettedSigningKeysCounts,
         Signature calldata sig
     ) external {
-        /// @dev The most likely reason for the signature to go stale
-        uint256 onchainNonce = STAKING_ROUTER.getStakingModuleNonce(stakingModuleId);
-        if (nonce != onchainNonce) revert ModuleNonceChanged();
-
-        uint256 nodeOperatorsCount = nodeOperatorIds.length / 8;
-
-        if (
-            nodeOperatorIds.length % 8 != 0 ||
-            vettedSigningKeysCounts.length % 16 != 0 ||
-            vettedSigningKeysCounts.length / 16 != nodeOperatorsCount ||
-            nodeOperatorsCount > maxOperatorsPerUnvetting
-        ) {
-            revert UnvetPayloadInvalid();
-        }
+        _checkIfUnvetPayloadValid(nodeOperatorIds, vettedSigningKeysCounts);
 
         address guardianAddr = msg.sender;
         int256 guardianIndex = _getGuardianIndex(msg.sender);
@@ -625,4 +617,23 @@ contract DepositSecurityModule {
             vettedSigningKeysCounts
         );
     }
+
+    function _checkIfUnvetPayloadValid(
+        uint256 stakingModuleId,
+        uint256 nonce,
+        bytes calldata nodeOperatorIds,
+        bytes calldata vettedSigningKeysCounts
+    ) internal view {
+        /// @dev The most likely reason for the signature to go stale
+        uint256 onchainNonce = STAKING_ROUTER.getStakingModuleNonce(stakingModuleId);
+        if (nonce != onchainNonce) revert ModuleNonceChanged();
+
+        uint256 nodeOperatorsCount = nodeOperatorIds.length / 8;
+
+        if (
+            nodeOperatorIds.length % 8 != 0 ||
+            vettedSigningKeysCounts.length != nodeOperatorsCount * 16 ||
+            nodeOperatorsCount > maxOperatorsPerUnvetting
+        ) revert UnvetPayloadInvalid();
+    }
 }

contracts/0.8.9/interfaces/IStakingModule.sol

@@ -23,7 +23,7 @@ interface IStakingModule {
 
     /// @notice Returns all-validators summary belonging to the node operator with the given id
     /// @param _nodeOperatorId id of the operator to return report for
-    /// @return targetLimitMode shows whether the current target limit applied to the node operator (0 = disabled, 1 = soft mode, 2 = forced mode)
+    /// @return targetLimitMode shows whether the current target limit applied to the node operator (0 = disabled, 1 = soft mode, 2 = boosted mode)
     /// @return targetValidatorsCount relative target active validators limit for operator
     /// @return stuckValidatorsCount number of validators with an expired request to exit time
     /// @return refundedValidatorsCount number of validators that can't be withdrawn, but deposit

contracts/0.8.9/oracle/AccountingOracle.sol

@@ -132,7 +132,7 @@ contract AccountingOracle is BaseOracle {
     bytes32 internal constant EXTRA_DATA_PROCESSING_STATE_POSITION =
         keccak256("lido.AccountingOracle.extraDataProcessingState");
 
-    bytes32 internal constant ZERO_HASH = bytes32(0);
+    bytes32 internal constant ZERO_BYTES32 = bytes32(0);
 
     address public immutable LIDO;
     ILidoLocator public immutable LOCATOR;
@@ -275,15 +275,7 @@ contract AccountingOracle is BaseOracle {
         /// data for a report is possible after its processing deadline passes or a new data report
         /// arrives.
         ///
-        /// Depending on the size of the extra data, the processing might need to be split into
-        /// multiple transactions. Each transaction contains a chunk of report data (an array of items)
-        /// and the hash of the next transaction. The last transaction will contain ZERO_HASH
-        /// as the next transaction hash.
-        ///
-        /// | 32 bytes |    array of items
-        /// | nextHash |         ...
-        ///
-        /// Each item being encoded as follows:
+        /// Extra data is an array of items, each item being encoded as follows:
         ///
         ///    3 bytes    2 bytes      X bytes
         /// | itemIndex | itemType | itemPayload |
@@ -356,7 +348,7 @@ contract AccountingOracle is BaseOracle {
         /// @dev Hash of the extra data. See the constant defining a specific extra data
         /// format for the info on how to calculate the hash.
         ///
-        /// Must be set to a zero hash if the oracle report contains no extra data.
+        /// Must be set to a `ZERO_BYTES32` if the oracle report contains no extra data.
         ///
         bytes32 extraDataHash;
 
@@ -374,16 +366,25 @@ contract AccountingOracle is BaseOracle {
     ///
     uint256 public constant EXTRA_DATA_FORMAT_EMPTY = 0;
 
-    /// @notice The list format for the extra data array. Used when all extra data processing
-    /// fits into a single or multiple transactions.
+    /// @notice The list format for the extra data array. Used when the oracle reports contains extra data.
+    ///
+    /// Depending on the extra data size, it's passed within a single or multiple transactions.
+    /// Each transaction contains data consisting of 1) the keccak256 hash of the next
+    /// transaction's data or `ZERO_BYTES32` if there are no more data chunks, and 2) a chunk
+    /// of report data (an array of items).
+    ///
+    /// |                   32 bytes                       |     X bytes      |
+    /// |  Next transaction's data hash or `ZERO_BYTES32`  |  array of items  |
     ///
-    /// Depend on the extra data size it passed within a single or multiple transactions.
-    /// Each transaction contains next transaction hash and a bytearray containing data items
-    /// packed tightly.
+    /// The `extraDataHash` field of the `ReportData` struct is calculated as a keccak256 hash
+    /// over the first transaction's data, i.e. over the first data chunk with the second
+    /// transaction's data hash (or `ZERO_BYTES32`) prepended.
     ///
-    /// Hash is a keccak256 hash calculated over the transaction data (next transaction hash and bytearray items).
-    /// The Solidity equivalent of the hash calculation code would be `keccak256(data)`,
-    /// where `data` has the `bytes` type.
+    /// ReportData.extraDataHash := hash0
+    /// hash0 := keccak256(| hash1 | extraData[0], ... extraData[n] |)
+    /// hash1 := keccak256(| hash2 | extraData[n + 1], ... extraData[m] |)
+    /// ...
+    /// hashK := keccak256(| ZERO_BYTES32 | extraData[x + 1], ... extraData[extraDataItemsCount] |)
     ///
     uint256 public constant EXTRA_DATA_FORMAT_LIST = 1;
 
@@ -420,7 +421,7 @@ contract AccountingOracle is BaseOracle {
 
     /// @notice Submits report extra data in the EXTRA_DATA_FORMAT_LIST format for processing.
     ///
-    /// @param data The extra data chunk with items list. See docs for the `EXTRA_DATA_FORMAT_LIST`
+    /// @param data  The extra data chunk. See docs for the `EXTRA_DATA_FORMAT_LIST`
     ///              constant for details.
     ///
     function submitReportExtraDataList(bytes calldata data) external {
@@ -461,7 +462,7 @@ contract AccountingOracle is BaseOracle {
         ConsensusReport memory report = _storageConsensusReport().value;
         result.currentFrameRefSlot = _getCurrentRefSlot();
 
-        if (report.hash == ZERO_HASH || result.currentFrameRefSlot != report.refSlot) {
+        if (report.hash == ZERO_BYTES32 || result.currentFrameRefSlot != report.refSlot) {
             return result;
         }
 
@@ -585,8 +586,8 @@ contract AccountingOracle is BaseOracle {
 
     function _handleConsensusReportData(ReportData calldata data, uint256 prevRefSlot) internal {
         if (data.extraDataFormat == EXTRA_DATA_FORMAT_EMPTY) {
-            if (data.extraDataHash != ZERO_HASH) {
-                revert UnexpectedExtraDataHash(ZERO_HASH, data.extraDataHash);
+            if (data.extraDataHash != ZERO_BYTES32) {
+                revert UnexpectedExtraDataHash(ZERO_BYTES32, data.extraDataHash);
             }
             if (data.extraDataItemsCount != 0) {
                 revert UnexpectedExtraDataItemsCount(0, data.extraDataItemsCount);
@@ -598,7 +599,7 @@ contract AccountingOracle is BaseOracle {
             if (data.extraDataItemsCount == 0) {
                 revert ExtraDataItemsCountCannotBeZeroForNonEmptyData();
             }
-            if (data.extraDataHash == ZERO_HASH) {
+            if (data.extraDataHash == ZERO_BYTES32) {
                 revert ExtraDataHashCannotBeZeroForNonEmptyData();
             }
         }
@@ -708,7 +709,7 @@ contract AccountingOracle is BaseOracle {
 
         ConsensusReport memory report = _storageConsensusReport().value;
 
-        if (report.hash == ZERO_HASH || procState.refSlot != report.refSlot) {
+        if (report.hash == ZERO_BYTES32 || procState.refSlot != report.refSlot) {
             revert CannotSubmitExtraDataBeforeMainData();
         }
 
@@ -757,7 +758,7 @@ contract AccountingOracle is BaseOracle {
         _processExtraDataItems(data, iter);
         uint256 itemsProcessed = iter.index + 1;
 
-        if (dataHash == ZERO_HASH) {
+        if (dataHash == ZERO_BYTES32) {
             if (itemsProcessed != procState.itemsCount) {
                 revert UnexpectedExtraDataItemsCount(procState.itemsCount, itemsProcessed);
             }

test/0.8.9/stakingRouter/stakingRouter.module-sync.test.ts

@@ -340,7 +340,7 @@ describe("StakingRouter:module-sync", () => {
 
   context("updateTargetValidatorsLimits", () => {
     const NODE_OPERATOR_ID = 0n;
-    const TARGET_LIMIT_MODE = 1; // 1 - soft, i.e. on WQ request; 2 - forced
+    const TARGET_LIMIT_MODE = 1; // 1 - soft, i.e. on WQ request; 2 - boosted
     const TARGET_LIMIT = 100n;
 
     it("Reverts if the caller does not have the role", async () => {