MetaMask
diff --git a/‎packages/assets-controllers/src/TokenDetectionController.test.ts‎
Lines changed: 1 addition & 0 deletions b/‎packages/assets-controllers/src/TokenDetectionController.test.ts‎
Lines changed: 1 addition & 0 deletions
diff --git a/‎packages/network-controller/src/NetworkController.ts‎
Lines changed: 49 additions & 0 deletions b/‎packages/network-controller/src/NetworkController.ts‎
Lines changed: 49 additions & 0 deletions
@@ -1157,6 +1157,7 @@ describe('TokenDetectionController', () => {
                 '0xe704',
                 '0xe705',
                 '0xe708',
+                '0x18c6',
               ],
               selectedAddress: secondSelectedAccount.address,
             });
 
@@ -13,6 +13,9 @@ import {
   ChainId,
   NetworksTicker,
   NetworkNickname,
+  BUILT_IN_CUSTOM_NETWORKS_RPC,
+  BUILT_IN_NETWORKS,
+  BuiltInNetworkName,
 } from '@metamask/controller-utils';
 import EthQuery from '@metamask/eth-query';
 import { errorCodes } from '@metamask/rpc-errors';
@@ -627,6 +630,21 @@ export type NetworkControllerOptions = {
 function getDefaultNetworkConfigurationsByChainId(): Record<
   Hex,
   NetworkConfiguration
+> {
+  return {
+    ...getDefaultInfuraNetworkConfigurationsByChainId(),
+    ...getDefaultCustomNetworkConfigurationsByChainId(),
+  };
+}
+
+/**
+ * Constructs a `networkConfigurationsByChainId` object for all default Infura networks.
+ *
+ * @returns The `networkConfigurationsByChainId` object of all Infura networks.
+ */
+function getDefaultInfuraNetworkConfigurationsByChainId(): Record<
+  Hex,
+  NetworkConfiguration
 > {
   return Object.values(InfuraNetworkType).reduce<
     Record<Hex, NetworkConfiguration>
@@ -657,6 +675,37 @@ function getDefaultNetworkConfigurationsByChainId(): Record<
   }, {});
 }
 
+/**
+ * Constructs a `networkConfigurationsByChainId` object for all default custom networks.
+ *
+ * @returns The `networkConfigurationsByChainId` object of all custom networks.
+ */
+function getDefaultCustomNetworkConfigurationsByChainId(): Record<
+  Hex,
+  NetworkConfiguration
+> {
+  const { ticker, rpcPrefs } =
+    BUILT_IN_NETWORKS[BuiltInNetworkName.MegaETHTestnet];
+  return {
+    [ChainId[BuiltInNetworkName.MegaETHTestnet]]: {
+      blockExplorerUrls: [rpcPrefs.blockExplorerUrl],
+      chainId: ChainId[BuiltInNetworkName.MegaETHTestnet],
+      defaultRpcEndpointIndex: 0,
+      defaultBlockExplorerUrlIndex: 0,
+      name: NetworkNickname[BuiltInNetworkName.MegaETHTestnet],
+      nativeCurrency: ticker,
+      rpcEndpoints: [
+        {
+          failoverUrls: [],
+          networkClientId: BuiltInNetworkName.MegaETHTestnet,
+          type: RpcEndpointType.Custom,
+          url: BUILT_IN_CUSTOM_NETWORKS_RPC.MEGAETH_TESTNET,
+        },
+      ],
+    },
+  };
+}
+
 /**
  * Constructs properties for the NetworkController state whose values will be
  * used if not provided to the constructor.