diff --git a/.github/workflows/deploy-site.yml b/.github/workflows/deploy-site.yml
index 01362ca3..368c9590 100644
--- a/.github/workflows/deploy-site.yml
+++ b/.github/workflows/deploy-site.yml
@@ -20,6 +20,7 @@ on:
       - "scripts/generate_site.py"
       - "scripts/hashing.py"
       - "scripts/largefiles.py"
+      - "scripts/mkdocs_hooks.py"
       - "scripts/nativemode.py"
       - "scripts/packextras.py"
       - "scripts/packpaths.py"
diff --git a/mkdocs.yml b/mkdocs.yml
index d57622d2..ab6ca2e8 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -8,6 +8,9 @@ repo_name: Abdess/retrobios
 # Almost every page is generated from platforms/, emulators/ and database.json,
 # so a per-page edit link would point at a file that does not exist.
 edit_uri: ''
+# lastmod in the sitemap from each page's own date, or none at all.
+hooks:
+  - scripts/mkdocs_hooks.py
 # Working notes kept under docs/ during development are not part of the site.
 exclude_docs: |
   plans/
diff --git a/scripts/generate_site.py b/scripts/generate_site.py
index 877770af..2e8951fc 100644
--- a/scripts/generate_site.py
+++ b/scripts/generate_site.py
@@ -1309,7 +1309,9 @@ def decorate_markdown_pages(docs: Path) -> None:
             "generated_by: retrobios-site\n"
             f"title: {json.dumps(browser_title, ensure_ascii=False)}\n"
             f"description: {json.dumps(description, ensure_ascii=False)}\n"
-            "---\n\n"
+            + (f"date_modified: {json.dumps(str(structured['dateModified']))}\n"
+               if structured.get("dateModified") else "")
+            + "---\n\n"
             '<script type="application/ld+json">\n'
             f"{structured_json}\n"
             "</script>\n\n"
@@ -1916,14 +1918,14 @@ def _system_file_card(f: dict, consumers: FileConsumers) -> list[str]:
         # The card named a file, its hashes and provenance, but not where to
         # get it: a user missing scph5501.bin found the reference and no way
         # to the bytes.
-        lines.append(f"- Collection path: `{f['path']}` ([download]({_fetch_url(f['path'])}))")
+        lines.append(f"- Collection path: {_code(f['path'])} ([download]({_fetch_url(f['path'])}))")
     # Every hash in full: the site search indexes text, not a title
     # attribute, so a pasted md5 or crc32 (what clrmamepro, RomVault or an
     # emulator log prints) found nothing behind a 12-character prefix.
     for label, value in (("SHA1", sha1_full), ("MD5", md5_full),
                          ("CRC32", f.get("crc32")), ("SHA256", f.get("sha256"))):
         if value and value != "unknown":
-            lines.append(f'- {label}: <span class="rb-hash">`{value}`</span>')
+            lines.append(f'- {label}: <span class="rb-hash">{_code(value)}</span>')
     if plats:
         plat_badges = " ".join(
             f'<span class="rb-badge rb-badge-info">[{p}](../platforms/{p}.md)</span>'
@@ -2293,7 +2295,7 @@ def _render_emulator_file(
         # byte-swapped 16-bit words, so the raw Adler-32 the downloads carry
         # for the same file differs, and the card says which one it lists.
         values = fadler32 if isinstance(fadler32, list) else [fadler32]
-        shown = ", ".join(f"`{str(v).lower().removeprefix('0x')}`" for v in values)
+        shown = ", ".join(_code(str(v).lower().removeprefix("0x")) for v in values)
         if f.get("adler32_byteswap"):
             details.append(
                 f"Adler32 over the file's 16-bit words byte-swapped: {shown} "
@@ -2328,7 +2330,8 @@ def _render_emulator_file(
             if len(parts) >= 3 and parts[0] == "bios":
                 page = parts[1].lower().replace(" ", "-")
                 details.append(
-                    f"Collection copy: [`{held}`](../systems/{page}.md#sha1-{sha1[:12]})"
+                    f"Collection copy: [{_code(held)}]"
+                    f"(../systems/{urllib.parse.quote(page)}.md#sha1-{sha1[:12]})"
                 )
         plats = sorted(consumers.platforms.get(sha1, ())) if sha1 else []
         if plats:
@@ -2895,7 +2898,8 @@ def _render_problem_files(platform_problems: list, settled: list | None = None)
         ])
         for p in sorted(settled, key=lambda row: (row["name"], row["platform"])):
             lines.append(
-                f"| `{p['name']}` | {p['platform']} | {p['status']} | `{p['held_by']}` |"
+                f"| {_code(p['name'])} | {_escape_tags(p['platform'])} | {p['status']} "
+                f"| {_code(p['held_by'])} |"
             )
         lines.append("")
 
@@ -3318,7 +3322,7 @@ def generate_gap_analysis(
             emulators = sorted({emulator for emulator, _name in bundled_rows})
             lines.extend([
                 f"{len(bundled_rows)} further files arrive with their emulator's own "
-                f"package ({', '.join(emulators)}): documented in the profile, not "
+                f"package ({_escape_tags(', '.join(emulators))}): documented in the profile, not "
                 "collected, and not listed here.",
                 "",
             ])
@@ -4178,6 +4182,9 @@ repo_name: Abdess/retrobios
 # Almost every page is generated from platforms/, emulators/ and database.json,
 # so a per-page edit link would point at a file that does not exist.
 edit_uri: ''
+# lastmod in the sitemap from each page's own date, or none at all.
+hooks:
+  - scripts/mkdocs_hooks.py
 # Working notes kept under docs/ during development are not part of the site.
 exclude_docs: |
   plans/
@@ -4323,6 +4330,7 @@ from siterender import (  # noqa: E402,F401
     _fmt_size,
     _pct,
     _admonition_body,
+    _code,
     _escape_tags,
     _icon_name,
     _icon_url,
diff --git a/scripts/mkdocs_hooks.py b/scripts/mkdocs_hooks.py
new file mode 100644
index 00000000..9d6bba27
--- /dev/null
+++ b/scripts/mkdocs_hooks.py
@@ -0,0 +1,17 @@
+"""MkDocs hooks for the generated site.
+
+The sitemap gave all 664 pages the build date as lastmod, so the field told
+a crawler nothing. A page whose content carries its own date (an emulator
+page: the day its profile was last read against the source) states it in
+its front matter; the rest get no lastmod rather than an inexact one.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+
+def on_page_markdown(markdown: str, page: Any, config: Any, files: Any) -> str:  # noqa: ARG001
+    """Take lastmod from the page's own date, or leave it out."""
+    page.update_date = str(page.meta.get("date_modified") or "")
+    return markdown
diff --git a/scripts/siterender.py b/scripts/siterender.py
index ee84ce86..6a10fb3f 100644
--- a/scripts/siterender.py
+++ b/scripts/siterender.py
@@ -20,6 +20,16 @@ _icon_available: dict[str, bool] = {}
 _CODE_SPAN = re.compile(r"(`+).+?\1", re.S)
 
 
+def _code(value: object) -> str:
+    """A value as an inline code span it cannot leave.
+
+    Markdown shows HTML inside a code span as text, so the one way out is a
+    backtick in the value closing the span early. Data from a profile, a
+    platform file or a file name is not ours to trust that far.
+    """
+    return "`" + str(value).replace("`", "'") + "`"
+
+
 def _escape_tags(text: str) -> str:
     """Show a placeholder such as ``<system_dir>`` as it was written.
 
diff --git a/tests/test_audit_regressions.py b/tests/test_audit_regressions.py
index b62115ef..e36b82d9 100644
--- a/tests/test_audit_regressions.py
+++ b/tests/test_audit_regressions.py
@@ -4638,5 +4638,37 @@ class VersionAnchorsFollowContent(unittest.TestCase):
                          ["file-audio-abs-6904b-v1-12", "file-audio-abs-6904b-v1-13"])
 
 
+
+class SitemapDatesComeFromThePage(unittest.TestCase):
+    """All 664 sitemap URLs carried the build date: eduke32, re-read on
+    2026-10-04, was announced as changed on the day of every build."""
+
+    def test_the_hook_takes_the_page_date_or_none(self):
+        from types import SimpleNamespace
+
+        from scripts.mkdocs_hooks import on_page_markdown
+
+        dated = SimpleNamespace(meta={"date_modified": "2026-10-04"}, update_date="today")
+        undated = SimpleNamespace(meta={}, update_date="today")
+        on_page_markdown("", dated, None, None)
+        on_page_markdown("", undated, None, None)
+        self.assertEqual((dated.update_date, undated.update_date), ("2026-10-04", ""))
+        config = (ROOT / "mkdocs.yml").read_text(encoding="utf-8")
+        self.assertIn("hooks:\n  - scripts/mkdocs_hooks.py", config)
+
+
+class SiteCodeSpansHoldTheirValue(unittest.TestCase):
+    """Values from profiles, platform files and file names went into code
+    spans as they were: a backtick in one closed the span and what followed
+    was read as markup."""
+
+    def test_a_backtick_cannot_close_the_span(self):
+        from scripts.siterender import _code
+
+        span = _code("a`<img src=x onerror=alert(1)>`")
+        self.assertEqual(span.count("`"), 2)
+        self.assertTrue(span.startswith("`") and span.endswith("`"))
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_workflow_paths.py b/tests/test_workflow_paths.py
index 64e4de62..3c66765b 100644
--- a/tests/test_workflow_paths.py
+++ b/tests/test_workflow_paths.py
@@ -9,6 +9,7 @@ from __future__ import annotations
 
 import ast
 import fnmatch
+import re
 import sys
 import unittest
 from pathlib import Path
@@ -78,6 +79,15 @@ class DeploySiteTriggers(unittest.TestCase):
             }
         )
         self.assertIn("generate_site.py", entry_points)
+        # mkdocs build runs the hooks mkdocs.yml names: a script of the build.
+        # The file carries Python tags safe_load refuses; the list is plain.
+        mkdocs = (REPO_ROOT / "mkdocs.yml").read_text(encoding="utf-8")
+        hooks = re.search(r"^hooks:\n((?:  - .+\n)+)", mkdocs, re.M)
+        entry_points += [
+            line.strip()[2:].removeprefix("scripts/")
+            for line in (hooks.group(1).splitlines() if hooks else [])
+            if line.strip()[2:].startswith("scripts/")
+        ]
         uncovered = sorted(
             path
             for path in closure(entry_points)