diff --git a/api/GlobalEventHandlers.json b/api/GlobalEventHandlers.json
index ac623598fcdd68..1f6a61eb9edf44 100644
--- a/api/GlobalEventHandlers.json
+++ b/api/GlobalEventHandlers.json
@@ -1004,44 +1004,6 @@
             "deprecated": false
           }
         }
-      },
-      "onslotchange": {
-        "__compat": {
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/GlobalEventHandlers/onslotchange",
-          "spec_url": "https://html.spec.whatwg.org/multipage/webappapis.html#handler-onslotchange",
-          "support": {
-            "chrome": {
-              "version_added": "97"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "93"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": {
-              "version_added": false
-            },
-            "safari": {
-              "version_added": "preview"
-            },
-            "safari_ios": {
-              "version_added": false
-            },
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
       }
     }
   }
diff --git a/api/HTMLSlotElement.json b/api/HTMLSlotElement.json
index b0977451ff2b60..8a002d48ac9b9f 100644
--- a/api/HTMLSlotElement.json
+++ b/api/HTMLSlotElement.json
@@ -173,7 +173,10 @@
         "__compat": {
           "description": "<code>slotchange</code> event",
           "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLSlotElement/slotchange_event",
-          "spec_url": "https://html.spec.whatwg.org/multipage/indices.html#event-slotchange",
+          "spec_url": [
+            "https://html.spec.whatwg.org/multipage/indices.html#event-slotchange",
+            "https://html.spec.whatwg.org/multipage/webappapis.html#handler-onslotchange"
+          ],
           "support": {
             "chrome": {
               "version_added": "53"
diff --git a/api/ShadowRoot.json b/api/ShadowRoot.json
index 8a4bb762c0d970..0c09adf42b3c6a 100644
--- a/api/ShadowRoot.json
+++ b/api/ShadowRoot.json
@@ -235,78 +235,6 @@
             "deprecated": false
           }
         }
-      },
-      "slotchange_event": {
-        "__compat": {
-          "description": "<code>slotchange</code> event",
-          "spec_url": "https://dom.spec.whatwg.org/#dom-shadowroot-onslotchange",
-          "support": {
-            "chrome": [
-              {
-                "version_added": "97"
-              },
-              {
-                "version_added": "53",
-                "version_removed": "97",
-                "partial_implementation": true,
-                "notes": "The <code>onslotchange</code> event handler property is not supported."
-              }
-            ],
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": [
-              {
-                "version_added": "93"
-              },
-              {
-                "version_added": "63",
-                "version_removed": "93",
-                "partial_implementation": true,
-                "notes": "The <code>onslotchange</code> event handler property is not supported."
-              }
-            ],
-            "firefox_android": [
-              {
-                "version_added": "93"
-              },
-              {
-                "version_added": "79",
-                "version_removed": "97",
-                "partial_implementation": true,
-                "notes": "The <code>onslotchange</code> event handler property is not supported."
-              }
-            ],
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": [
-              {
-                "version_added": "14.1"
-              },
-              {
-                "version_added": "10.1",
-                "version_removed": "14.1",
-                "partial_implementation": true,
-                "notes": "The <code>onslotchange</code> event handler property is not supported."
-              }
-            ],
-            "safari_ios": "mirror",
-            "samsunginternet_android": {
-              "version_added": "6.0",
-              "partial_implementation": true,
-              "notes": "The <code>onslotchange</code> event handler property is not supported."
-            },
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
       }
     }
   }