diff --git a/client-hints/resources/sec-ch-ua.py b/client-hints/resources/sec-ch-ua.py
index 01bcb9682a1ae9d..ddeb582a19bc8e4 100644
--- a/client-hints/resources/sec-ch-ua.py
+++ b/client-hints/resources/sec-ch-ua.py
@@ -1,8 +1,6 @@
 def main(request, response):
-    ua = request.headers.get(b'sec-ch-ua', b'')
+    ua = request.headers.get(b'Sec-CH-UA', b'')
     response.headers.set(b"Content-Type", b"text/html")
-    response.headers.set(b"Accept-CH", b"UA")
-    response.headers.set(b"Accept-CH-Lifetime", b"10")
     response.content = b'''
 <script>
   window.opener.postMessage({ header: '%s' }, "*");
diff --git a/client-hints/sec-ch-ua.https.html b/client-hints/sec-ch-ua.https.html
index bc7a1a8f7d9eaba..deb81692165f1c0 100644
--- a/client-hints/sec-ch-ua.https.html
+++ b/client-hints/sec-ch-ua.https.html
@@ -3,39 +3,48 @@
 <script src=/resources/testharness.js></script>
 <script src=/resources/testharnessreport.js></script>
 <script>
-  var minor = "";
-  promise_test(t => {
+  var sec_ch_ua_header = "";
+
+  function grabSECCHUAHeader(t) {
     return new Promise((resolve, reject) => {
       var w;
       window.onmessage = e => {
         try {
-          assert_not_equals(e.data.header, "", "The `Sec-CH-UA` header is delivered.");
-          minor = e.data.header;
+          resolve(e.data.header)
         } catch (ex) {
           reject(ex);
         }
-        w.close();
-        resolve();
       };
       w = window.open("./resources/sec-ch-ua.py");
+      t.add_cleanup(w.close);
+    });
+  }
+  promise_test(t => {
+    return grabSECCHUAHeader(t).then(header => {
+      sec_ch_ua_header = header;
+      assert_not_equals(sec_ch_ua_header, "", "`Sec-CH-UA` is sent.");
     });
-  }, "Open HTTPS window prior to opt-in: `Sec-CH-UA` header with minor version.")
+  }, "Open HTTPS window: `Sec-CH-UA` header returned by default.");
 
   promise_test(t => {
-    return new Promise((resolve, reject) => {
-      var w;
-      window.onmessage = e => {
-        try {
-          assert_not_equals(e.data.header, "", "The `Sec-CH-UA` header is delivered.");
-          assert_equals(e.data.header, minor, "The `Sec-CH-UA` header did not change after the opt-in.");
-        } catch (ex) {
-          reject(ex);
-        }
-        w.close();
-        resolve();
-      };
-      w = window.open("./resources/sec-ch-ua.py");
+    return grabSECCHUAHeader(t).then(header => {
+      assert_not_equals(header, "", "The `Sec-CH-UA` header is delivered.");
+      assert_equals(header, sec_ch_ua_header,
+        "The `Sec-CH-UA` header did not change between requests.");
+    });
+  }, "Open HTTPS window: `Sec-CH-UA` header is consistent across versions.");
+
+  promise_test(t => {
+    return grabSECCHUAHeader(t).then(header => {
+      assert_true(header.split(", ").every((brand) => {
+        let brandEnd = brand.indexOf(";v=");
+        assert_true(brandEnd !== -1,
+          "A well-formed Sec-CH-UA header must have version (v=) params");
+        /* 32 + 2, becuase of the extra quotes padding the brand,
+           e.g. '"lol";v=22"' */
+        return brandEnd < 34;
+      }));
     });
-  }, "Open HTTPS window post-opt-in: `Sec-CH-UA` header with minor version.")
+  }, "Open HTTPS window: No brand in `Sec-CH-UA` header is > than 32 chars.");
 </script>
 </head>
diff --git a/ua-client-hints/useragentdata.https.any.js b/ua-client-hints/useragentdata.https.any.js
new file mode 100644
index 000000000000000..fc1e9e0b3c98907
--- /dev/null
+++ b/ua-client-hints/useragentdata.https.any.js
@@ -0,0 +1,7 @@
+// META: title=tests for navigator.userAgentData
+
+test(t => {
+  const brands = navigator.userAgentData.brands;
+  assert_true(brands.every(brand => brand.brand.length < 32),
+    "No brand should be longer than 32 characters.");
+});