diff --git a/api/ExtendableCookieChangeEvent.json b/api/ExtendableCookieChangeEvent.json
index 74606ab50f45b4..ebf74c54324ad5 100644
--- a/api/ExtendableCookieChangeEvent.json
+++ b/api/ExtendableCookieChangeEvent.json
@@ -21,7 +21,14 @@
           "opera": "mirror",
           "opera_android": "mirror",
           "safari": {
-            "version_added": "18.4"
+            "version_added": "18.4",
+            "flags": [
+              {
+                "name": "Cookie Store API CookieStoreManager",
+                "type": "preference",
+                "value_to_set": "Enabled"
+              }
+            ]
           },
           "safari_ios": "mirror",
           "samsunginternet_android": "mirror",
@@ -56,7 +63,14 @@
             "opera": "mirror",
             "opera_android": "mirror",
             "safari": {
-              "version_added": "18.4"
+              "version_added": "18.4",
+              "flags": [
+                {
+                  "name": "Cookie Store API CookieStoreManager",
+                  "type": "preference",
+                  "value_to_set": "Enabled"
+                }
+              ]
             },
             "safari_ios": "mirror",
             "samsunginternet_android": "mirror",
@@ -91,7 +105,14 @@
             "opera": "mirror",
             "opera_android": "mirror",
             "safari": {
-              "version_added": "18.4"
+              "version_added": "18.4",
+              "flags": [
+                {
+                  "name": "Cookie Store API CookieStoreManager",
+                  "type": "preference",
+                  "value_to_set": "Enabled"
+                }
+              ]
             },
             "safari_ios": "mirror",
             "samsunginternet_android": "mirror",
@@ -125,7 +146,14 @@
               "opera": "mirror",
               "opera_android": "mirror",
               "safari": {
-                "version_added": "18.4"
+                "version_added": "18.4",
+                "flags": [
+                  {
+                    "name": "Cookie Store API CookieStoreManager",
+                    "type": "preference",
+                    "value_to_set": "Enabled"
+                  }
+                ]
               },
               "safari_ios": "mirror",
               "samsunginternet_android": "mirror",
@@ -161,7 +189,14 @@
             "opera": "mirror",
             "opera_android": "mirror",
             "safari": {
-              "version_added": "18.4"
+              "version_added": "18.4",
+              "flags": [
+                {
+                  "name": "Cookie Store API CookieStoreManager",
+                  "type": "preference",
+                  "value_to_set": "Enabled"
+                }
+              ]
             },
             "safari_ios": "mirror",
             "samsunginternet_android": "mirror",
@@ -195,7 +230,14 @@
               "opera": "mirror",
               "opera_android": "mirror",
               "safari": {
-                "version_added": "18.4"
+                "version_added": "18.4",
+                "flags": [
+                  {
+                    "name": "Cookie Store API CookieStoreManager",
+                    "type": "preference",
+                    "value_to_set": "Enabled"
+                  }
+                ]
               },
               "safari_ios": "mirror",
               "samsunginternet_android": "mirror",