diff --git a/css/css-scoping/has-slotted-001.tentative.html b/css/css-scoping/has-slotted-001.tentative.html
new file mode 100644
index 00000000000000..9a9563287631b6
--- /dev/null
+++ b/css/css-scoping/has-slotted-001.tentative.html
@@ -0,0 +1,23 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>:has-slotted(*)</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586">
+<link rel="match" href="/css/reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="host">
+    <template shadowrootmode="open">
+      <style>
+        slot {
+          display: block;
+          width: 100px;
+          height: 100px;
+          background-color: red;
+        }
+        :has-slotted(*) {
+          background-color: green;
+        }
+      </style>
+      <slot></slot>
+    </template>
+    <div></div>
+</div>
\ No newline at end of file
diff --git a/css/css-scoping/has-slotted-002.tentative.html b/css/css-scoping/has-slotted-002.tentative.html
new file mode 100644
index 00000000000000..a67f788f785633
--- /dev/null
+++ b/css/css-scoping/has-slotted-002.tentative.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>:has-slotted(...) negative test: no children or white space</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586">
+<link rel="match" href="/css/reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="host"><template shadowrootmode="open">
+    <style>
+    slot {
+        display: block;
+        width: 100px;
+        height: 100px;
+        background-color: green;
+    }
+    :has-slotted(*) {
+        background-color: red;
+    }
+    </style>
+    <slot></slot>
+</template></div>
\ No newline at end of file
diff --git a/css/css-scoping/has-slotted-003.tentative.html b/css/css-scoping/has-slotted-003.tentative.html
new file mode 100644
index 00000000000000..9565b1594c3ed7
--- /dev/null
+++ b/css/css-scoping/has-slotted-003.tentative.html
@@ -0,0 +1,22 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>:has-slotted(...) negative test: no children, but whitespace present</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586">
+<link rel="match" href="/css/reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="host">
+    <template shadowrootmode="open">
+        <style>
+        slot {
+            display: block;
+            width: 100px;
+            height: 100px;
+            background-color: green;
+        }
+        :has-slotted(*) {
+            background-color: red;
+        }
+        </style>
+        <slot></slot>
+    </template>
+</div>
\ No newline at end of file
diff --git a/css/css-scoping/has-slotted-004.tentative.html b/css/css-scoping/has-slotted-004.tentative.html
new file mode 100644
index 00000000000000..2d980e10051eb5
--- /dev/null
+++ b/css/css-scoping/has-slotted-004.tentative.html
@@ -0,0 +1,23 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>:has-slotted(.class)</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586">
+<link rel="match" href="/css/reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="host">
+    <template shadowrootmode="open">
+      <style>
+        slot {
+          display: block;
+          width: 100px;
+          height: 100px;
+          background-color: red;
+        }
+        :has-slotted(.slotted-element) {
+          background-color: green;
+        }
+      </style>
+      <slot></slot>
+    </template>
+    <div class="slotted-element"></div>
+</div>
\ No newline at end of file
diff --git a/css/css-scoping/has-slotted-005.tentative.html b/css/css-scoping/has-slotted-005.tentative.html
new file mode 100644
index 00000000000000..3de7c16f287cb6
--- /dev/null
+++ b/css/css-scoping/has-slotted-005.tentative.html
@@ -0,0 +1,23 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>:has-slotted(.class) negative test</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586">
+<link rel="match" href="/css/reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="host">
+    <template shadowrootmode="open">
+      <style>
+        slot {
+          display: block;
+          width: 100px;
+          height: 100px;
+          background-color: green;
+        }
+        :has-slotted(.not-slotted-element) {
+          background-color: red;
+        }
+      </style>
+      <slot></slot>
+    </template>
+    <div class="slotted-element"></div>
+</div>
\ No newline at end of file
diff --git a/css/css-scoping/has-slotted-006.tentative.html b/css/css-scoping/has-slotted-006.tentative.html
new file mode 100644
index 00000000000000..aea5c6b2a141fd
--- /dev/null
+++ b/css/css-scoping/has-slotted-006.tentative.html
@@ -0,0 +1,25 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>:has-slotted(el) + :has-slotted(el)</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586">
+<link rel="match" href="/css/reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="host">
+    <template shadowrootmode="open">
+      <style>
+        [name] {
+          display: block;
+          width: 100px;
+          height: 100px;
+          background-color: red;
+        }
+        :has-slotted(div) + :has-slotted(div) {
+          background-color: green;
+        }
+      </style>
+      <slot></slot>
+      <slot name="after"></slot>
+    </template>
+    <div></div>
+    <div slot="after"></div>
+</div>
\ No newline at end of file
diff --git a/css/selectors/parsing/parse-has-slotted.tentative.html b/css/selectors/parsing/parse-has-slotted.tentative.html
new file mode 100644
index 00000000000000..3e240f677fbda4
--- /dev/null
+++ b/css/selectors/parsing/parse-has-slotted.tentative.html
@@ -0,0 +1,32 @@
+<!doctype html>
+<meta charset="utf-8" />
+<title>CSS Selectors: has slotted pseudo selectors</title>
+<link rel="help" href="https://github.com/w3c/csswg-drafts/pull/10586" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+<script>
+  test_valid_selector(":has-slotted(bar)");
+  test_valid_selector(':has-slotted([attr="foo"])');
+  test_valid_selector(":has-slotted(*)");
+  test_valid_selector(":has-slotted(.class)");
+  test_valid_selector(":has-slotted(#id)");
+  test_valid_selector(":has-slotted(:not(foo))");
+  test_valid_selector(':has-slotted(:not(:nth-last-of-type(2)):not([slot="foo"]))');
+  test_valid_selector(":has-slotted(:first-child)");
+  test_valid_selector(":has-slotted(:hover)");
+  test_valid_selector(":has-slotted(foo):first-child");
+  test_valid_selector(":has-slotted(foo):hover");
+  test_valid_selector(":has-slotted(foo):focus");
+  test_valid_selector(":has-slotted(foo):lang(en)");
+  test_valid_selector(":has-slotted(foo):dir(ltr)");
+  test_valid_selector(':has-slotted(foo) + :has-slotted(bar)');
+  test_valid_selector(":not(:has-slotted(foo))");
+  test_valid_selector(":has-slotted(div + div)");
+  test_valid_selector(":has-slotted(div:has(> span))");
+  test_invalid_selector("::has-slotted(foo)");
+  test_invalid_selector(":has-slotted");
+  test_invalid_selector(":has-slotted()");
+  test_invalid_selector(":has-slotted(0)");
+  test_invalid_selector(":has-slotted(div > span)");
+</script>
\ No newline at end of file
