OK, it was decided that MAX_SCRIPT_ELEMENT_SIZE shall be 3072.

src/net_processing.cpp

@@ -2798,7 +2798,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
         std::vector<unsigned char> vData;
         vRecv >> vData;
 
-        // Nodes must NEVER send a data item > 520 bytes (the max size for a script data object,
+        // Nodes must NEVER send a data item > MAX_SCRIPT_ELEMENT_SIZE bytes (the max size for a script data object,
         // and thus, the maximum size any matched object can have) in a filteradd message
         bool bad = false;
         if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) {

src/policy/policy.cpp

@@ -99,7 +99,7 @@ bool IsStandardTx(const CTransaction& tx, std::string& reason, const bool witnes
     for (const CTxIn& txin : tx.vin)
     {
         // Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed
-        // keys (remember the 520 byte limit on redeemScript size). That works
+        // keys (remember the MAX_SCRIPT_ELEMENT_SIZE byte limit on redeemScript size). That works
         // out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)+3=1627
         // bytes of scriptSig, which we round off to 1650 bytes for some minor
         // future-proofing. That's also enough to spend a 20-of-20

src/script/script.h

@@ -20,7 +20,7 @@
 #include <vector>
 
 // Maximum number of bytes pushable to the stack
-static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520;
+static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 3072;
 
 // Maximum number of non-push operations per script
 static const int MAX_OPS_PER_SCRIPT = 201;

src/wallet/wallet.cpp

@@ -4352,7 +4352,7 @@ std::vector<CTxDestination> GetAllDestinationsForKey(const CPubKey& key)
 
 CTxDestination CWallet::AddAndGetDestinationForScript(const CScript& script, OutputType type)
 {
-    // Note that scripts over 520 bytes are not yet supported.
+    // Note that scripts over MAX_SCRIPT_ELEMENT_SIZE bytes are not yet supported.
     switch (type) {
     case OUTPUT_TYPE_LEGACY:
         return CScriptID(script);