Preview highlight help

Does sombody know which flow reach this callback in preview package and how to test it?

I have checked it, and it’s for code block highlighting. When you write something like this:

```js
console.log('Hello, World!');
```

Here is a diff I made, and I could see the expected error stack trace:

diff --git a/packages/preview/src/browser/markdown/markdown-preview-handler.spec.ts b/packages/preview/src/browser/markdown/markdown-preview-handler.spec.ts
index fa06b93ba..84fdd075a 100644
--- a/packages/preview/src/browser/markdown/markdown-preview-handler.spec.ts
+++ b/packages/preview/src/browser/markdown/markdown-preview-handler.spec.ts
@@ -76,6 +76,10 @@ describe('markdown-preview-handler', () => {
         await assertRenderedContent(exampleMarkdown5, exampleHtml5);
     });
 
+    it('renders code block', async () => {
+        await assertRenderedContent(exampleMarkdown6, '');
+    });
+
     it('finds element for source line', () => {
         document.body.innerHTML = exampleHtml1;
         const element = previewHandler.findElementForSourceLine(document.body, 4);
@@ -201,6 +205,12 @@ const exampleHtml5 = //
 </p>
 `;
 
+const exampleMarkdown6 = `
+\`\`\`js
+console.log(Date.now());
+\`\`\`
+`;
+
 /**
  * `offsetTop` of elements to be `sourceLine` number times `20`.
  */
diff --git a/packages/preview/src/browser/markdown/markdown-preview-handler.ts b/packages/preview/src/browser/markdown/markdown-preview-handler.ts
index c354b61c0..0bd51a345 100644
--- a/packages/preview/src/browser/markdown/markdown-preview-handler.ts
+++ b/packages/preview/src/browser/markdown/markdown-preview-handler.ts
@@ -220,6 +220,7 @@ export class MarkdownPreviewHandler implements PreviewHandler {
                 linkify: true,
                 highlight: (str, lang) => {
                     if (lang && hljs.getLanguage(lang)) {
+                        console.log(new Error('HERE calling the callback'));
                         try {
                             return '<pre class="hljs"><code><div>' + hljs.highlight(lang, str, true).value + '</div></code></pre>';
                         } catch { }

I hope this helps