diff --git a/api/Document.json b/api/Document.json
index a3b3107ffdd506..ae2120ed7850dd 100644
--- a/api/Document.json
+++ b/api/Document.json
@@ -6627,155 +6627,6 @@
           }
         }
       },
-      "transitioncancel_event": {
-        "__compat": {
-          "description": "<code>transitioncancel</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Document/transitioncancel_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitioncancel",
-          "support": {
-            "chrome": {
-              "version_added": "74"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionend_event": {
-        "__compat": {
-          "description": "<code>transitionend</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Document/transitionend_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionend",
-          "support": {
-            "chrome": {
-              "version_added": false
-            },
-            "chrome_android": "mirror",
-            "edge": {
-              "version_added": "12"
-            },
-            "firefox": {
-              "version_added": "51"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": "10",
-              "notes": "The <code>ontransitionend</code> attribute is not supported in IE. To listen to this event, use <code>document.addEventListener('transitionend', function() {});</code>."
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "11"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionrun_event": {
-        "__compat": {
-          "description": "<code>transitionrun</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Document/transitionrun_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionrun",
-          "support": {
-            "chrome": {
-              "version_added": false
-            },
-            "chrome_android": "mirror",
-            "edge": {
-              "version_added": "12"
-            },
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": "10",
-              "notes": "The <code>ontransitionrun</code> attribute is not supported in IE. To listen to this event, use <code>document.addEventListener('transitionrun', function() {});</code>."
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionstart_event": {
-        "__compat": {
-          "description": "<code>transitionstart</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Document/transitionstart_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionstart",
-          "support": {
-            "chrome": {
-              "version_added": false
-            },
-            "chrome_android": "mirror",
-            "edge": {
-              "version_added": "12"
-            },
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": "10",
-              "notes": "The <code>ontransitionstart</code> attribute is not supported in IE. To listen to this event, use <code>document.addEventListener('transitionstart', function() {});</code>."
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
       "visibilitychange_event": {
         "__compat": {
           "description": "<code>visibilitychange</code> event",
diff --git a/api/Element.json b/api/Element.json
index d4637d26f185a6..630f3a507b5f0a 100644
--- a/api/Element.json
+++ b/api/Element.json
@@ -6840,6 +6840,238 @@
           }
         }
       },
+      "transitioncancel_event": {
+        "__compat": {
+          "description": "<code>transitioncancel</code> event",
+          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Element/transitioncancel_event",
+          "spec_url": [
+            "https://drafts.csswg.org/css-transitions/#transitioncancel",
+            "https://drafts.csswg.org/css-transitions/#dom-globaleventhandlers-ontransitioncancel"
+          ],
+          "support": {
+            "chrome": [
+              {
+                "version_added": "87"
+              },
+              {
+                "version_added": "74",
+                "partial_implementation": true,
+                "notes": "The <code>ontransitioncancel</code> event handler property is not supported. To listen to this event, use <code>element.addEventListener('transitioncancel', function() {});</code>."
+              }
+            ],
+            "chrome_android": "mirror",
+            "edge": "mirror",
+            "firefox": {
+              "version_added": "53"
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": [
+              {
+                "version_added": "13.1"
+              },
+              {
+                "version_added": "12",
+                "partial_implementation": true,
+                "notes": "Although the <code>ontransitioncancel</code> property is supported, the <code>transitioncancel</code> event is never fired."
+              }
+            ],
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror"
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "transitionend_event": {
+        "__compat": {
+          "description": "<code>transitionend</code> event",
+          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Element/transitionend_event",
+          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionend",
+          "support": {
+            "chrome": [
+              {
+                "version_added": "26"
+              },
+              {
+                "alternative_name": "webkittransitionend",
+                "version_added": "1"
+              }
+            ],
+            "chrome_android": "mirror",
+            "edge": [
+              {
+                "version_added": "18"
+              },
+              {
+                "version_added": "12",
+                "partial_implementation": true,
+                "notes": "The <code>ontransitionend</code> event handler property is not supported. To listen to this event, use <code>element.addEventListener('transitionend', function() {});</code>."
+              },
+              {
+                "alternative_name": "webkittransitionend",
+                "version_added": "79"
+              }
+            ],
+            "firefox": {
+              "version_added": "51"
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": "10",
+              "partial_implementation": true,
+              "notes": "The <code>ontransitionend</code> event handler property is not supported. To listen to this event, use <code>element.addEventListener('transitionend', function() {});</code>."
+            },
+            "oculus": "mirror",
+            "opera": [
+              {
+                "version_added": "12.1"
+              },
+              {
+                "alternative_name": "webkittransitionend",
+                "version_added": "15"
+              },
+              {
+                "alternative_name": "otransitionend",
+                "version_added": "11.6",
+                "version_removed": "15"
+              }
+            ],
+            "opera_android": [
+              {
+                "version_added": "12.1"
+              },
+              {
+                "alternative_name": "webkittransitionend",
+                "version_added": "14"
+              },
+              {
+                "alternative_name": "otransitionend",
+                "version_added": "12",
+                "version_removed": "14"
+              }
+            ],
+            "safari": [
+              {
+                "version_added": "7"
+              },
+              {
+                "alternative_name": "webkittransitionend",
+                "version_added": "4"
+              }
+            ],
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror"
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "transitionrun_event": {
+        "__compat": {
+          "description": "<code>transitionrun</code> event",
+          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Element/transitionrun_event",
+          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionrun",
+          "support": {
+            "chrome": {
+              "version_added": "74"
+            },
+            "chrome_android": "mirror",
+            "edge": {
+              "version_added": "12"
+            },
+            "firefox": {
+              "version_added": "53"
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": "10",
+              "partial_implementation": true,
+              "notes": "The <code>ontransitionrun</code> event handler property is not supported. To listen to this event, use <code>element.addEventListener('transitionrun', function() {});</code>."
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": [
+              {
+                "version_added": "13.1"
+              },
+              {
+                "version_added": "12",
+                "partial_implementation": true,
+                "notes": "The event handler exists but will never be called."
+              }
+            ],
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror"
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "transitionstart_event": {
+        "__compat": {
+          "description": "<code>transitionstart</code> event",
+          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Element/transitionstart_event",
+          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionstart",
+          "support": {
+            "chrome": {
+              "version_added": "74"
+            },
+            "chrome_android": "mirror",
+            "edge": {
+              "version_added": "12"
+            },
+            "firefox": {
+              "version_added": "53"
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": "10",
+              "partial_implementation": true,
+              "notes": "The <code>ontransitionstart</code> event handler property is not supported. To listen to this event, use <code>element.addEventListener('transitionstart', function() {});</code>."
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": [
+              {
+                "version_added": "13.1"
+              },
+              {
+                "version_added": "12",
+                "partial_implementation": true,
+                "notes": "The event handler exists but will never be called."
+              }
+            ],
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror"
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
       "webkitmouseforcechanged_event": {
         "__compat": {
           "description": "<code>webkitmouseforcechanged</code> event",
diff --git a/api/GlobalEventHandlers.json b/api/GlobalEventHandlers.json
index b21192ede579ad..46d7ea0192f87a 100644
--- a/api/GlobalEventHandlers.json
+++ b/api/GlobalEventHandlers.json
@@ -1120,220 +1120,6 @@
             "deprecated": false
           }
         }
-      },
-      "ontransitioncancel": {
-        "__compat": {
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/GlobalEventHandlers/ontransitioncancel",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#ref-for-dom-globaleventhandlers-ontransitioncancel",
-          "support": {
-            "chrome": {
-              "version_added": "87"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": {
-              "version_added": false
-            },
-            "safari": [
-              {
-                "version_added": "13.1"
-              },
-              {
-                "version_added": "12",
-                "partial_implementation": true,
-                "notes": "The event handler is exposed but will not actually be called unless both the \"Web Animations\" and \"CSS Animations via Web Animations\" preferences are enabled."
-              }
-            ],
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "ontransitionend": {
-        "__compat": {
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/GlobalEventHandlers/ontransitionend",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#ref-for-dom-globaleventhandlers-ontransitionend",
-          "support": {
-            "chrome": [
-              {
-                "version_added": "79"
-              },
-              {
-                "version_added": "81",
-                "alternative_name": "onwebkittransitionend"
-              },
-              {
-                "version_added": "26",
-                "version_removed": "79",
-                "partial_implementation": true,
-                "notes": "Only supported on the <code>Window</code> interface."
-              }
-            ],
-            "chrome_android": "mirror",
-            "edge": [
-              {
-                "version_added": "18"
-              },
-              {
-                "version_added": "81",
-                "alternative_name": "onwebkittransitionend"
-              }
-            ],
-            "firefox": {
-              "version_added": "51"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false,
-              "notes": "The <code>ontransitionend</code> attribute is not supported in IE. To listen to this event, use <code>document.addEventListener('transitionend', function() {});</code>."
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": [
-              {
-                "version_added": "57"
-              },
-              {
-                "version_added": "59",
-                "alternative_name": "onwebkittransitionend"
-              },
-              {
-                "version_added": "14",
-                "version_removed": "57",
-                "partial_implementation": true,
-                "notes": "Only supported on the <code>Window</code> interface."
-              }
-            ],
-            "safari": {
-              "version_added": "11"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": [
-              {
-                "version_added": "11.0"
-              },
-              {
-                "version_added": "13.0",
-                "alternative_name": "onwebkittransitionend"
-              },
-              {
-                "version_added": "1.5",
-                "version_removed": "11.0",
-                "partial_implementation": true,
-                "notes": "Only supported on the <code>Window</code> interface."
-              }
-            ],
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "ontransitionrun": {
-        "__compat": {
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/GlobalEventHandlers/ontransitionrun",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#ref-for-dom-globaleventhandlers-ontransitionrun",
-          "support": {
-            "chrome": {
-              "version_added": "87"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false,
-              "notes": "The <code>ontransitionrun</code> attribute is not supported in IE. To listen to this event, use <code>document.addEventListener('transitionrun', function() {});</code>."
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": {
-              "version_added": false
-            },
-            "safari": [
-              {
-                "version_added": "13.1"
-              },
-              {
-                "version_added": "12",
-                "partial_implementation": true,
-                "notes": "The event handler is exposed but will not actually be called unless both the \"Web Animations\" and \"CSS Animations via Web Animations\" preferences are enabled."
-              }
-            ],
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "ontransitionstart": {
-        "__compat": {
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/GlobalEventHandlers/ontransitionstart",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#ref-for-dom-globaleventhandlers-ontransitionstart",
-          "support": {
-            "chrome": {
-              "version_added": "87"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false,
-              "notes": "The <code>ontransitionstart</code> attribute is not supported in IE. To listen to this event, use <code>document.addEventListener('transitionstart', function() {});</code>."
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": {
-              "version_added": false
-            },
-            "safari": [
-              {
-                "version_added": "13.1"
-              },
-              {
-                "version_added": "12",
-                "partial_implementation": true,
-                "notes": "The event handler is exposed but will not actually be called unless both the \"Web Animations\" and \"CSS Animations via Web Animations\" preferences are enabled."
-              }
-            ],
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
       }
     }
   }
diff --git a/api/HTMLElement.json b/api/HTMLElement.json
index 48d007439394c9..d4006af4a534e2 100644
--- a/api/HTMLElement.json
+++ b/api/HTMLElement.json
@@ -1988,210 +1988,6 @@
           }
         }
       },
-      "transitioncancel_event": {
-        "__compat": {
-          "description": "<code>transitioncancel</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLElement/transitioncancel_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitioncancel",
-          "support": {
-            "chrome": {
-              "version_added": "74"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionend_event": {
-        "__compat": {
-          "description": "<code>transitionend</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLElement/transitionend_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionend",
-          "support": {
-            "chrome": [
-              {
-                "version_added": "26"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "1"
-              }
-            ],
-            "chrome_android": "mirror",
-            "edge": [
-              {
-                "version_added": "12"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "79"
-              }
-            ],
-            "firefox": {
-              "version_added": "51"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": "10"
-            },
-            "oculus": "mirror",
-            "opera": [
-              {
-                "version_added": "12.1"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "15"
-              },
-              {
-                "alternative_name": "oTransitionEnd",
-                "version_added": "11.6",
-                "version_removed": "15"
-              }
-            ],
-            "opera_android": [
-              {
-                "version_added": "12.1"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "14"
-              },
-              {
-                "alternative_name": "oTransitionEnd",
-                "version_added": "12",
-                "version_removed": "14"
-              }
-            ],
-            "safari": [
-              {
-                "version_added": "7"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "4"
-              }
-            ],
-            "safari_ios": [
-              {
-                "version_added": "7"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "3.2"
-              }
-            ],
-            "samsunginternet_android": "mirror",
-            "webview_android": [
-              {
-                "version_added": "≤37"
-              },
-              {
-                "alternative_name": "webkitTransitionEnd",
-                "version_added": "≤37"
-              }
-            ]
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionrun_event": {
-        "__compat": {
-          "description": "<code>transitionrun</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLElement/transitionrun_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionrun",
-          "support": {
-            "chrome": {
-              "version_added": "74"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionstart_event": {
-        "__compat": {
-          "description": "<code>transitionstart</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLElement/transitionstart_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionstart",
-          "support": {
-            "chrome": {
-              "version_added": "74"
-            },
-            "chrome_android": "mirror",
-            "edge": {
-              "version_added": "12"
-            },
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": "10"
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
       "translate": {
         "__compat": {
           "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLElement/translate",
diff --git a/api/Window.json b/api/Window.json
index e2ace82c1f7cbc..474dc02536fa9e 100644
--- a/api/Window.json
+++ b/api/Window.json
@@ -6416,146 +6416,6 @@
           }
         }
       },
-      "transitioncancel_event": {
-        "__compat": {
-          "description": "<code>transitioncancel</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Window/transitioncancel_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitioncancel",
-          "support": {
-            "chrome": {
-              "version_added": "74"
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionend_event": {
-        "__compat": {
-          "description": "<code>transitionend</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Window/transitionend_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionend",
-          "support": {
-            "chrome": {
-              "version_added": false
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "51"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionrun_event": {
-        "__compat": {
-          "description": "<code>transitionrun</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Window/transitionrun_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionrun",
-          "support": {
-            "chrome": {
-              "version_added": false
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
-      "transitionstart_event": {
-        "__compat": {
-          "description": "<code>transitionstart</code> event",
-          "mdn_url": "https://developer.mozilla.org/docs/Web/API/Window/transitionstart_event",
-          "spec_url": "https://drafts.csswg.org/css-transitions/#transitionstart",
-          "support": {
-            "chrome": {
-              "version_added": false
-            },
-            "chrome_android": "mirror",
-            "edge": "mirror",
-            "firefox": {
-              "version_added": "53"
-            },
-            "firefox_android": "mirror",
-            "ie": {
-              "version_added": false
-            },
-            "oculus": "mirror",
-            "opera": "mirror",
-            "opera_android": "mirror",
-            "safari": {
-              "version_added": "13.1"
-            },
-            "safari_ios": "mirror",
-            "samsunginternet_android": "mirror",
-            "webview_android": "mirror"
-          },
-          "status": {
-            "experimental": false,
-            "standard_track": true,
-            "deprecated": false
-          }
-        }
-      },
       "unhandledrejection_event": {
         "__compat": {
           "description": "<code>unhandledrejection</code> event",