diff --git a/api/TransformStream.json b/api/TransformStream.json
index cb316f53b18189..985ef590503e79 100644
--- a/api/TransformStream.json
+++ b/api/TransformStream.json
@@ -94,7 +94,8 @@
             "spec_url": "https://streams.spec.whatwg.org/#dom-transformer-cancel",
             "support": {
               "chrome": {
-                "version_added": false
+                "version_added": false,
+                "impl_url": "https://crbug.com/40283531"
               },
               "chrome_android": "mirror",
               "deno": {
@@ -102,7 +103,8 @@
               },
               "edge": "mirror",
               "firefox": {
-                "version_added": false
+                "version_added": false,
+                "impl_url": "https://bugzil.la/1856103"
               },
               "firefox_android": "mirror",
               "ie": {
@@ -115,7 +117,8 @@
               "opera": "mirror",
               "opera_android": "mirror",
               "safari": {
-                "version_added": false
+                "version_added": false,
+                "impl_url": "https://webkit.org/b/262424"
               },
               "safari_ios": "mirror",
               "samsunginternet_android": "mirror",