@@ -12,9 +12,7 @@ describe("maskMarkdownFrontmatter", () => {
   });
 
   it("handles a byte order mark, CR line endings, and a ... closing fence", () => {
-    expect(maskMarkdownFrontmatter("\uFEFF---\na: 1\n---\n# Body")).toBe(
-      "\uFEFF   \n    \n   \n# Body",
-    );
+    expect(maskMarkdownFrontmatter("\uFEFF---\na: 1\n---\n# Body")).toBe("    \n    \n   \n# Body");
     expect(maskMarkdownFrontmatter("---\ra: 1\r...\r# Body")).toBe("   \r    \r   \r# Body");
     expect(maskMarkdownFrontmatter("---\n---\n# Body")).toBe("   \n   \n# Body");
   });
 
@@ -1,14 +1,11 @@
 const LEADING_FRONTMATTER =
-  /^(\uFEFF?)(---[ \t]*(?:\r\n|\r|\n)(?:[\s\S]*?(?:\r\n|\r|\n))?(?:---|\.\.\.)[ \t]*)(?=\r\n|\r|\n|$)/;
+  /^\uFEFF?---[ \t]*(?:\r\n|\r|\n)(?:[\s\S]*?(?:\r\n|\r|\n))?(?:---|\.\.\.)[ \t]*(?=\r\n|\r|\n|$)/;
 
 /**
  * Blanks a leading YAML frontmatter block so rendered previews skip it instead
  * of showing a rule and a setext heading. Masked characters become spaces and
  * line breaks stay, so source offsets (task checkbox edits) stay valid.
  */
 export function maskMarkdownFrontmatter(markdown: string): string {
-  return markdown.replace(
-    LEADING_FRONTMATTER,
-    (_match, bom: string, block: string) => bom + block.replace(/[^\r\n]/g, " "),
-  );
+  return markdown.replace(LEADING_FRONTMATTER, (block) => block.replace(/[^\r\n]/g, " "));
 }