rpc, log: add backgroundvalidation to getblockchaininfo

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 5156f658..dc6473b9 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1374,12 +1374,21 @@ RPCHelpMan getblockchaininfo()
                 {RPCResult::Type::NUM, "headers", "the current number of headers we have validated"},
                 {RPCResult::Type::STR, "bestblockhash", "the hash of the currently best block"},
                 {RPCResult::Type::STR_HEX, "bits", "nBits: compact representation of the block difficulty target"},
-                {RPCResult::Type::STR_HEX, "target", "The difficulty target"},
+                {RPCResult::Type::STR_HEX, "target", "the difficulty target"},
                 {RPCResult::Type::NUM, "difficulty", "the current difficulty"},
-                {RPCResult::Type::NUM_TIME, "time", "The block time expressed in " + UNIX_EPOCH_TIME},
-                {RPCResult::Type::NUM_TIME, "mediantime", "The median block time expressed in " + UNIX_EPOCH_TIME},
+                {RPCResult::Type::NUM_TIME, "time", "the block time expressed in " + UNIX_EPOCH_TIME},
+                {RPCResult::Type::NUM_TIME, "mediantime", "the median block time expressed in " + UNIX_EPOCH_TIME},
                 {RPCResult::Type::NUM, "verificationprogress", "estimate of verification progress [0..1]"},
                 {RPCResult::Type::BOOL, "initialblockdownload", "(debug information) estimate of whether this node is in Initial Block Download mode"},
+                {RPCResult::Type::OBJ, "backgroundvalidation", /*optional=*/true, "state info regarding background validation process",
+                {
+                    {RPCResult::Type::NUM, "snapshotheight", "the height of the snapshot block. Background validation verifies the chain from genesis up to this height"},
+                    {RPCResult::Type::NUM, "blocks", "the height of the most-work background fully-validated chain. The genesis block has height 0"},
+                    {RPCResult::Type::STR, "bestblockhash", "the hash of the currently best block validated in the background"},
+                    {RPCResult::Type::NUM_TIME, "mediantime", "the median block time expressed in " + UNIX_EPOCH_TIME},
+                    {RPCResult::Type::NUM, "verificationprogress", "estimate of background verification progress [0..1]"},
+                    {RPCResult::Type::STR_HEX, "chainwork", "total amount of work in background validated chain, in hexadecimal"},
+                }},
                 {RPCResult::Type::STR_HEX, "chainwork", "total amount of work in active chain, in hexadecimal"},
                 {RPCResult::Type::NUM, "size_on_disk", "the estimated size of the block and undo files on disk"},
                 {RPCResult::Type::BOOL, "pruned", "if the blocks are subject to pruning"},
@@ -1420,6 +1429,19 @@ RPCHelpMan getblockchaininfo()
     obj.pushKV("mediantime", tip.GetMedianTimePast());
     obj.pushKV("verificationprogress", chainman.GuessVerificationProgress(&tip));
     obj.pushKV("initialblockdownload", chainman.IsInitialBlockDownload());
+    auto historical_blocks{chainman.GetHistoricalBlockRange()};
+    if (historical_blocks) {
+        UniValue background_validation(UniValue::VOBJ);
+        const CBlockIndex& btip{*CHECK_NONFATAL(historical_blocks->first)};
+        const CBlockIndex& btarget{*CHECK_NONFATAL(historical_blocks->second)};
+        background_validation.pushKV("snapshotheight", btarget.nHeight);
+        background_validation.pushKV("blocks", btip.nHeight);
+        background_validation.pushKV("bestblockhash", btip.GetBlockHash().GetHex());
+        background_validation.pushKV("mediantime", btip.GetMedianTimePast());
+        background_validation.pushKV("chainwork", btip.nChainWork.GetHex());
+        background_validation.pushKV("verificationprogress", chainman.GetBackgroundVerificationProgress(btip));
+        obj.pushKV("backgroundvalidation", std::move(background_validation));
+    }
     obj.pushKV("chainwork", tip.nChainWork.GetHex());
     obj.pushKV("size_on_disk", chainman.m_blockman.CalculateCurrentUsage());
     obj.pushKV("pruned", chainman.m_blockman.IsPruneMode());
diff --git a/test/functional/rpc_blockchain.py b/test/functional/rpc_blockchain.py
index cecd0c03..18a67ce5 100755
--- a/test/functional/rpc_blockchain.py
+++ b/test/functional/rpc_blockchain.py
@@ -170,6 +170,9 @@ class BlockchainTest(BitcoinTestFramework):
         assert res['pruned']
         assert not res['automatic_pruning']
 
+        # check background validation is not present when we are not using assumeutxo
+        assert "backgroundvalidation" not in res.keys()
+
         self.restart_node(0, ['-stopatheight=207'])
         res = self.nodes[0].getblockchaininfo()
         # should have exact keys