diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index fca25d8..b1d1e74 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -114,8 +114,13 @@ jobs:
       # And its output must match what is committed, so a hand-edit to a
       # generated file, or a source change that was never regenerated, fails
       # here rather than shipping.
+      # Every generated artefact is listed, and the generator is timestamp-free
+      # by design (T-ENG03) — a run-date in any header would fail this on day two.
       - name: Assert generated output is current
-        run: git diff --exit-code -- data/entries docs/data.js docs/incidents.js
+        run: >-
+          git diff --exit-code --
+          data/entries data/backlinks.json
+          docs/data.js docs/backlinks.js docs/frameworks-registry.js docs/incidents.js
 
   unit-tests:
     name: Unit tests
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a2311bf..37350d3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -122,6 +122,28 @@ the corresponding JSON file in `/data/`. The schema is in
 [`data/schema.json`](data/schema.json). This keeps the machine-readable
 layer in sync with the markdown.
 
+### Generated files
+
+`data/entries/*.json`, `data/backlinks.json` and the webapp bundles
+(`docs/data.js`, `docs/backlinks.js`, `docs/frameworks-registry.js`,
+`docs/incidents.js`) are **written by `scripts/generate.js`, never by hand**.
+`data/stats.json` and the README badges come from `npm run stats`.
+
+The build is deterministic: running `npm run build` twice on the same
+sources produces byte-identical output, and the generated files carry no
+run date, machine name or other build-time value. CI regenerates everything
+and fails on any diff, so after changing a mapping file run:
+
+```bash
+npm run build          # generate → validate → stats:check
+npm test               # includes the determinism and bundle checks
+git diff --exit-code   # must be clean apart from your intended change
+```
+
+GitHub Pages serves `docs/` straight from `main`, which is why the bundles
+are committed rather than built on deploy. Keep it that way unless the
+Pages source is deliberately switched to a workflow-based deploy.
+
 ---
 
 ## Code of conduct
diff --git a/docs/backlinks.js b/docs/backlinks.js
index f323dd8..1c4a46e 100644
--- a/docs/backlinks.js
+++ b/docs/backlinks.js
@@ -1,5 +1,4 @@
 // Auto-generated by scripts/generate.js — do not edit manually
-// Generated: 2026-08-28
 // Backlinks: 1159
 window.CROSSWALK_BACKLINKS = [
   {
diff --git a/docs/data.js b/docs/data.js
index 8442fd5..ab2b5c1 100644
--- a/docs/data.js
+++ b/docs/data.js
@@ -1,6 +1,5 @@
 // Auto-generated by scripts/generate.js — do not edit manually
-// Source: OWASP GenAI Crosswalk v1.5.2
-// Generated: 2026-08-28
+// Source: OWASP GenAI Crosswalk v4.0.0
 // Entries: 51
 window.CROSSWALK_DATA = [
   {
diff --git a/docs/frameworks-registry.js b/docs/frameworks-registry.js
index c6abd6c..efa9a1b 100644
--- a/docs/frameworks-registry.js
+++ b/docs/frameworks-registry.js
@@ -1,5 +1,4 @@
 // Auto-generated by scripts/generate.js — do not edit manually
-// Generated: 2026-08-28
 // Frameworks: 25
 window.CROSSWALK_FRAMEWORKS = [
   {
diff --git a/docs/incidents.js b/docs/incidents.js
index e329a5d..f8884a0 100644
--- a/docs/incidents.js
+++ b/docs/incidents.js
@@ -1,5 +1,4 @@
 // Auto-generated by scripts/generate.js — do not edit manually
-// Generated: 2026-08-28
 // Incidents: 131
 window.CROSSWALK_INCIDENTS = [
   {
diff --git a/scripts/generate.js b/scripts/generate.js
index d1804f1..f73a06a 100644
--- a/scripts/generate.js
+++ b/scripts/generate.js
@@ -841,15 +841,18 @@ function main() {
     allEntries.push(entry);
   }
 
-  // Write bundled site data for GitHub Pages query interface
+  // Write bundled site data for GitHub Pages query interface.
+  // Bundle headers are deliberately timestamp-free: docs/ is served straight
+  // from main and CI asserts `git diff --exit-code` on these files, so a
+  // generated-on date would make every checkout dirty the next day.
   if (!DRY_RUN && !SINGLE_ID) {
+    const PKG_VERSION = JSON.parse(fs.readFileSync(path.join(ROOT, 'package.json'), 'utf8')).version;
     const docsDir = path.join(ROOT, 'docs');
     fs.mkdirSync(docsDir, { recursive: true });
     const siteDataPath = path.join(docsDir, 'data.js');
     const siteData = [
       `// Auto-generated by scripts/generate.js — do not edit manually`,
-      `// Source: OWASP GenAI Crosswalk v1.5.2`,
-      `// Generated: ${new Date().toISOString().split('T')[0]}`,
+      `// Source: OWASP GenAI Crosswalk v${PKG_VERSION}`,
       `// Entries: ${allEntries.length}`,
       `window.CROSSWALK_DATA = ${JSON.stringify(allEntries, null, 2)};`,
     ].join('\n');
@@ -895,7 +898,6 @@ function main() {
     const siteBacklinksPath = path.join(docsDir, 'backlinks.js');
     const siteBacklinks = [
       `// Auto-generated by scripts/generate.js — do not edit manually`,
-      `// Generated: ${new Date().toISOString().split('T')[0]}`,
       `// Backlinks: ${backlinksArray.length}`,
       `window.CROSSWALK_BACKLINKS = ${JSON.stringify(backlinksArray, null, 2)};`,
     ].join('\n');
@@ -920,7 +922,6 @@ function main() {
       const fwRegistryPath = path.join(docsDir, 'frameworks-registry.js');
       const fwRegistryData = [
         `// Auto-generated by scripts/generate.js — do not edit manually`,
-        `// Generated: ${new Date().toISOString().split('T')[0]}`,
         `// Frameworks: ${fwRegistry.length}`,
         `window.CROSSWALK_FRAMEWORKS = ${JSON.stringify(fwRegistry, null, 2)};`,
       ].join('\n');
@@ -934,7 +935,6 @@ function main() {
       const incPath = path.join(docsDir, 'incidents.js');
       const incData = [
         `// Auto-generated by scripts/generate.js — do not edit manually`,
-        `// Generated: ${new Date().toISOString().split('T')[0]}`,
         `// Incidents: ${incDb.incidents.length}`,
         `window.CROSSWALK_INCIDENTS = ${JSON.stringify(incDb.incidents, null, 2)};`,
       ].join('\n');
diff --git a/scripts/generate.test.mjs b/scripts/generate.test.mjs
index 8c31dce..c531ae4 100644
--- a/scripts/generate.test.mjs
+++ b/scripts/generate.test.mjs
@@ -117,6 +117,20 @@ test('DRAFT never survives into a stored enum field', () => {
   assert.deepEqual(leaked.slice(0, 5), [], `${leaked.length} field(s) stored the literal "DRAFT"`);
 });
 
+test('webapp bundles carry no build timestamp', () => {
+  // docs/ is served straight from main and CI diffs these files against a
+  // fresh generation. A `// Generated: <date>` header made that diff fail on
+  // every day but the one the bundle was committed — so the header must
+  // describe the data, never the run.
+  for (const f of BUNDLES.filter((b) => fs.existsSync(b))) {
+    const header = fs.readFileSync(f, 'utf8').split(/\r?\n/).filter((l) => l.startsWith('//'));
+    for (const line of header) {
+      assert.doesNotMatch(line, /Generated:/i, `${path.basename(f)} header names a run: ${line}`);
+      assert.doesNotMatch(line, /\d{4}-\d{2}-\d{2}/, `${path.basename(f)} header carries a date: ${line}`);
+    }
+  }
+});
+
 test('webapp bundles stay in step with the entry files', () => {
   const src = fs.readFileSync(path.join(ROOT, 'docs', 'data.js'), 'utf8');
   const start = src.indexOf('[');