diff --git a/check2.tmp.ts b/check2.tmp.ts
new file mode 100644
index 00000000..f7c962d5
--- /dev/null
+++ b/check2.tmp.ts
@@ -0,0 +1,20 @@
+const lines = (await Bun.file('/tmp/addrs2.tsv').text()).trim().split('\n');
+let hits = 0, totalBal = 0;
+for (const line of lines) {
+  const [type, path, addr] = line.split('\t');
+  const proc = Bun.spawn(['curl', '-4', '-s', '--max-time', '12', `https://mempool.space/api/address/${addr}`], { stdout: 'pipe', stderr: 'ignore' });
+  const body = await new Response(proc.stdout).text();
+  await proc.exited;
+  try {
+    const j = JSON.parse(body); const c = j.chain_stats, m = j.mempool_stats;
+    const tx = (c?.tx_count ?? 0) + (m?.tx_count ?? 0);
+    if (tx > 0) {
+      const bal = (c.funded_txo_sum - c.spent_txo_sum) + (m.funded_txo_sum - m.spent_txo_sum);
+      totalBal += bal; hits++;
+      console.log(`${type} ${path} ${addr} txs=${tx} balance=${bal}`);
+    }
+  } catch {}
+  await Bun.sleep(70);
+}
+console.log(`\nindices20-59: addressesWithHistory=${hits} unspentTotal=${totalBal} sats`);
+process.exit(0);
diff --git a/src/servers/sidecar/wallet/chain-source-esplora.test.ts b/src/servers/sidecar/wallet/chain-source-esplora.test.ts
index e67a18f3..69ecaa07 100644
--- a/src/servers/sidecar/wallet/chain-source-esplora.test.ts
+++ b/src/servers/sidecar/wallet/chain-source-esplora.test.ts
@@ -7,6 +7,7 @@
 
 import { describe, expect, test } from 'bun:test';
 import { HDKey } from '@scure/bip32';
+import { mnemonicToSeedSync } from '@scure/bip39';
 import * as bitcoin from 'bitcoinjs-lib';
 import type { EsploraAddress, EsploraChain, EsploraTx, EsploraUtxo } from './chain';
 import { EsploraChainSource } from './chain-source-esplora';
@@ -15,9 +16,17 @@ import { initEcc } from './psbt';
 
 initEcc();
 
-// A published BIP32 test vector, so the addresses below are reproducible by anything that speaks BIP84.
-const ACCOUNT_XPUB =
-  'xpub6DQv646WnF2m1tkyhhwu74tes1MunPX8psKwjmXSmWcPExp7FR9XP2q6m8VcK9uZMQE3rDmPnTnEDTHSxcmad7wzBvLk8PXC7Gnxe5GUpUq';
+// NEVER PUT A REAL ACCOUNT KEY IN A TEST. An xpub cannot spend, but it reveals every address a wallet
+// will ever use and its entire history, permanently and irrevocably — and a test file is the easiest
+// place in a repo for one to hide, because it looks like a fixture. This one is derived here, in the
+// open, from the BIP84 specification's own published mnemonic, so its provenance is checkable rather
+// than asserted. If you need a different fixture, derive it the same way; do not paste one in.
+const PUBLIC_TEST_MNEMONIC =
+  'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about';
+
+const ACCOUNT_XPUB = HDKey.fromMasterSeed(mnemonicToSeedSync(PUBLIC_TEST_MNEMONIC)).derive(
+  "m/84'/0'/0'",
+).publicExtendedKey;
 
 /** Derive the same p2wpkh address the backend will, independently of the backend. */
 function addressAt(chain: 0 | 1, index: number): string {
@@ -141,6 +150,12 @@ function backendFor(world: Map<string, Funding>) {
 }
 
 describe('EsploraChainSource through OnchainBackend', () => {
+  test('the fixture key really is the published BIP84 vector, not somebody’s wallet', () => {
+    // The spec's own first receive address. If this fails, the mnemonic above is not what it claims and
+    // whatever replaced it must be treated as live key material until proven otherwise.
+    expect(addressAt(0, 0)).toBe('bc1qcr8te4kr609gcawutmrza0j4xv80jy8z306fyu');
+  });
+
   test('an empty wallet costs one gap-limit window per chain and reports zero', async () => {
     const { backend, stub } = backendFor(new Map());