diff --git a/api/WindowClient.json b/api/WindowClient.json
index f6b79a5731d72..1aa46795be449 100644
--- a/api/WindowClient.json
+++ b/api/WindowClient.json
@@ -35,6 +35,41 @@
           "deprecated": false
         }
       },
+      "ancestorOrigins": {
+        "__compat": {
+          "spec_url": "https://w3c.github.io/ServiceWorker/#client-ancestororigins",
+          "support": {
+            "chrome": {
+              "version_added": false
+            },
+            "chrome_android": "mirror",
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": "16"
+            },
+            "safari_ios": {
+              "version_added": false
+            },
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
       "focus": {
         "__compat": {
           "mdn_url": "https://developer.mozilla.org/docs/Web/API/WindowClient/focus",