diff --git a/packages/networks/src/defaults.spec.ts b/packages/networks/src/defaults.spec.ts
index 34615d891..43cd00e5a 100644
--- a/packages/networks/src/defaults.spec.ts
+++ b/packages/networks/src/defaults.spec.ts
@@ -6,22 +6,33 @@
 import { ledgerApps } from '@polkadot/hw-ledger/defaults';
 import { isHex } from '@polkadot/util';
 
-import { knownGenesis, knownLedger } from './defaults/index.js';
+import { knownGenesis, knownLedger, knownTestnet } from './defaults/index.js';
 
 describe('defaults', (): void => {
+  const genesisKeys = Object.keys(knownGenesis);
+  const ledgerKeys = Object.keys(knownLedger);
+
   describe('genesis', (): void => {
     it('has hex values for all genesis chains', (): void => {
       expect(
-        Object.keys(knownGenesis).filter((network) =>
+        genesisKeys.filter((network) =>
           !knownGenesis[network].length ||
           knownGenesis[network].some((g) => !isHex(g, 256))
         )
       ).toEqual([]);
     });
 
+    it('has no entries for testnets', (): void => {
+      expect(
+        genesisKeys.filter((network) =>
+          knownTestnet[network]
+        )
+      ).toEqual([]);
+    });
+
     it('has genesis for all Ledger chains', (): void => {
       expect(
-        Object.keys(knownLedger).filter((network) =>
+        ledgerKeys.filter((network) =>
           !knownGenesis[network]
         )
       ).toEqual([]);
@@ -31,7 +42,7 @@ describe('defaults', (): void => {
   describe('Ledger', (): void => {
     it('has entries for each of the apps (hwledger -> networks)', (): void => {
       expect(
-        Object.keys(knownLedger).filter((network) =>
+        ledgerKeys.filter((network) =>
           !ledgerApps[network]
         )
       ).toEqual([]);
diff --git a/packages/networks/src/defaults/genesis.ts b/packages/networks/src/defaults/genesis.ts
index 096814cf4..ec2a185d2 100644
--- a/packages/networks/src/defaults/genesis.ts
+++ b/packages/networks/src/defaults/genesis.ts
@@ -3,10 +3,14 @@
 
 import type { KnownGenesis } from '../types.js';
 
-// NOTE: In the case where the network was hard-spooned and multiple genesisHashes
-// are provided, it needs to be in reverse order, i.e. most-recent first, oldest
-// last. This make lookups for the current a simple genesisHash[0]
-// (See Kusama as an example)
+// In the case where the network was hard-spooned and multiple genesisHashes
+// are provided, it needs to be in reverse order, i.e. most-recent goes first,
+// oldest goes last. This make lookups for the current a simple genesisHash[0]
+// where the latest ios always the first entry (See Kusama as an example)
+//
+// IMPORTANT: Apart from the test relays, this list is limited to live parachains
+// and live production  networks. It does not and should not contain any testnets,
+// either stand-alone or connected to test relays such as Westend/Rococo
 export const knownGenesis: KnownGenesis = {
   acala: [
     '0xfc41b9bd8ef8fe53d58c7ea67c794c7ec9a73daf05e6d54b14ff6342c99ba64c'