diff --git a/dom.bs b/dom.bs
index bb16cf55..bbb24bf4 100644
--- a/dom.bs
+++ b/dom.bs
@@ -4936,7 +4936,8 @@ and an optional <a for=/>document</a> <dfn export for="clone a node"><var>docume
    <a for=Element>shadow root</a>'s <a for=ShadowRoot>mode</a>, true, <var>node</var>'s
    <a for=Element>shadow root</a>'s <a for=ShadowRoot>serializable</a>, <var>node</var>'s
    <a for=Element>shadow root</a>'s <a for=ShadowRoot>delegates focus</a>, <var>node</var>'s
-   <a for=Element>shadow root</a>'s <a for=ShadowRoot>slot assignment</a>, and
+   <a for=Element>shadow root</a>'s <a for=ShadowRoot>slot assignment</a>, <var>node</var>'s
+   <a for=Element>shadow root</a>'s <a for=ShadowRoot>reference target</a>, and
    <var>shadowRootRegistry</var>.
 
    <li><p>Set <var>copy</var>'s <a for=Element>shadow root</a>'s <a for=ShadowRoot>declarative</a>
@@ -6553,6 +6554,7 @@ interface ShadowRoot : DocumentFragment {
   readonly attribute boolean clonable;
   readonly attribute boolean serializable;
   readonly attribute Element host;
+  attribute DOMString? referenceTarget;
 
   attribute EventHandler onslotchange;
 };
@@ -6590,6 +6592,9 @@ It is initially set to false.</p>
 <p><a for=/>Shadow roots</a> have an associated <dfn for=ShadowRoot>serializable</dfn> (a boolean).
 It is initially set to false.</p>
 
+<p><a for=/>Shadow roots</a> have an associated <dfn export for=ShadowRoot>reference target</dfn>
+(null or a string). It is initially set to null.</p>
+
 <p><a for=/>Shadow roots</a> have an associated <dfn for=ShadowRoot>custom element registry</dfn>
 (null or a {{CustomElementRegistry}} object). It is initially null.</p>
 
@@ -6628,6 +6633,10 @@ null if <var>event</var>'s <a>composed flag</a> is unset and <a for=/>shadow roo
 <p>The <dfn attribute for=ShadowRoot><code>host</code></dfn> getter steps are to return
 <a>this</a>'s <a for=DocumentFragment>host</a>.
 
+<p>The <dfn attribute for=ShadowRoot><code>referenceTarget</code></dfn> getter steps are to return
+<a>this</a>'s <a for=ShadowRoot>reference target</a>. The {{ShadowRoot/referenceTarget}} setter
+steps are to set <a>this</a>'s <a for=ShadowRoot>reference target</a> to the given value.
+
 <hr>
 
 <p>The <dfn attribute for=ShadowRoot><code>onslotchange</code></dfn> attribute is an
@@ -6762,6 +6771,7 @@ dictionary ShadowRootInit {
   SlotAssignmentMode slotAssignment = "named";
   boolean clonable = false;
   boolean serializable = false;
+  DOMString? referenceTarget = null;
   CustomElementRegistry? customElementRegistry;
 };
 </pre>
@@ -7738,7 +7748,8 @@ are:
  <var>init</var>["{{ShadowRootInit/mode}}"], <var>init</var>["{{ShadowRootInit/clonable}}"],
  <var>init</var>["{{ShadowRootInit/serializable}}"],
  <var>init</var>["{{ShadowRootInit/delegatesFocus}}"],
- <var>init</var>["{{ShadowRootInit/slotAssignment}}"], and <var>registry</var>.
+ <var>init</var>["{{ShadowRootInit/slotAssignment}}"], and
+ <var>init</var>["{{ShadowRootInit/referenceTarget}}"], and <var>registry</var>.
 
  <li><p>Return <a>this</a>'s <a for=Element>shadow root</a>.
 </ol>
@@ -7748,7 +7759,8 @@ are:
 <p>To <dfn id=concept-attach-a-shadow-root>attach a shadow root</dfn>, given an
 <a for=/>element</a> <var>element</var>, a string <var>mode</var>, a boolean <var>clonable</var>,
 a boolean <var>serializable</var>, a boolean <var>delegatesFocus</var>, a string
-<var>slotAssignment</var>, and null or a {{CustomElementRegistry}} object <var>registry</var>:
+<var>slotAssignment</var>, null or a string <var>referenceTarget</var>, and null or a
+{{CustomElementRegistry}} object <var>registry</var>:
 
 <ol>
  <li><p>If <var>element</var>'s <a for=Element>namespace</a> is not the <a>HTML namespace</a>,
@@ -7822,6 +7834,8 @@ a boolean <var>serializable</var>, a boolean <var>delegatesFocus</var>, a string
 
  <li><p>Set <var>shadow</var>'s <a for=ShadowRoot>serializable</a> to <var>serializable</var>.
 
+ <li><p>Set <var>shadow</var>'s <a for=ShadowRoot>reference target</a> to <var>referenceTarget</var>.
+
  <li><p>Set <var>shadow</var>'s <a for=ShadowRoot>custom element registry</a> to
  <var>registry</var>.