test: fixme WebSocket locale test in Chromium 150

.github/workflows/fix-flakes-prompt.md

@@ -37,6 +37,11 @@ down your step-1 ranking, re-checking each; only stop once the whole shortlist i
   in that test's file since. Only move on if enough subsequent runs show the failures stopped;
   a browser roll alone is not evidence of a fix.
 
+Compare the test across every bot that runs it, not only the failing bot. A clean boundary
+between stable, beta, and dev browser channels often points to a browser-version regression.
+Read the exact versions from the job logs and record the failing and passing versions; channel
+names alone do not identify the affected behaviour.
+
 ## 3. Reproduce on this OS
 
 Read the test and its `error_message`.
@@ -77,6 +82,18 @@ Broader OS coverage comes from different agent runs on other OSes, not from you.
   it.fixme(browserName === 'webkit' && isLinux, 'https://github.com/microsoft/playwright/issues/NNNNN');
   ```
 
+  For browser-specific failures, prefer the narrowest observed version predicate over a channel
+  predicate. Channels roll forward, so `channel === 'chrome'` can keep skipping the test after
+  the browser fixes the bug. If stable fails while beta/dev passes, use `browserVersion` or
+  `browserMajorVersion` and gate only the affected version:
+
+  ```ts
+  it.fixme(browserName === 'chromium' && browserMajorVersion === 150, 'https://github.com/microsoft/playwright/issues/NNNNN');
+  ```
+
+  Do not invent a wider threshold for untested versions. Keep a channel predicate only when the
+  same browser version behaves differently between channels.
+
   Link an issue if one exists or explain why the test is skipped. **Default to `fixme`** — it parks
   the debt and stays greppable. Use `skip` only if reproduction shows the test is genuinely
   mis-scoped for that config (`skip` claims "this failure is expected and correct," which a

tests/library/browsercontext-locale.spec.ts

@@ -225,8 +225,9 @@ it('should send user Accept-Language header', {
 
 it('should send Accept-Language header on WebSocket handshake', {
   annotation: [{ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/23732' }],
-}, async ({ browser, server, browserName }) => {
+}, async ({ browser, server, browserName, browserMajorVersion }) => {
   it.fixme(browserName === 'firefox', 'Firefox does not send Accept-Language on WebSocket handshake');
+  it.fixme(browserName === 'chromium' && browserMajorVersion === 150, 'Chromium 150 sends the browser Accept-Language instead of the emulated locale on WebSocket handshake, https://github.com/microsoft/playwright/issues/23732');
   const context = await browser.newContext({ locale: 'en-GB' });
   const page = await context.newPage();
   await page.goto(server.EMPTY_PAGE);