diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
new file mode 100644
index 00000000000..fdaff2570dd
--- /dev/null
+++ b/features/javascript-discouraged.yml
@@ -0,0 +1,43 @@
+name: JavaScript built-ins (legacy)
+description: 
+spec: https://tc39.es/ecma262/multipage/
+group: javascript
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
+    - https://tc39.es/ecma262/#sec-object.prototype-legacy-accessor-methods
+    - https://tc39.es/ecma262/#sec-object.prototype.__proto__
+compat_features:
+  # The following properties are legacy according to:
+  # https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
+  - javascript.builtins.escape
+  - javascript.builtins.unescape
+  - javascript.builtins.String.anchor
+  - javascript.builtins.String.big
+  - javascript.builtins.String.blink
+  - javascript.builtins.String.bold
+  - javascript.builtins.String.fixed
+  - javascript.builtins.String.fontcolor
+  - javascript.builtins.String.fontsize
+  - javascript.builtins.String.italics
+  - javascript.builtins.String.link
+  - javascript.builtins.String.small
+  - javascript.builtins.String.strike
+  - javascript.builtins.String.sub
+  - javascript.builtins.String.substr
+  - javascript.builtins.String.sup
+  - javascript.builtins.Date.getYear
+  - javascript.builtins.Date.setYear
+  - javascript.builtins.Date.toGMTString
+  - javascript.builtins.RegExp.compile
+
+  # The following properties are legacy according to:
+  # https://tc39.es/ecma262/#sec-object.prototype-legacy-accessor-methods
+  - javascript.builtins.Object.defineGetter
+  - javascript.builtins.Object.defineSetter
+  - javascript.builtins.Object.lookupGetter
+  - javascript.builtins.Object.lookupSetter
+
+  # The following properties are legacy according to:
+  # https://tc39.es/ecma262/#sec-object.prototype.__proto__
+  - javascript.builtins.Object.proto
\ No newline at end of file
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
new file mode 100644
index 00000000000..ca1e072ba9a
--- /dev/null
+++ b/features/javascript-discouraged.yml.dist
@@ -0,0 +1,69 @@
+# Generated from: javascript-discouraged.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+status:
+  baseline: false
+  support:
+    chrome: "1"
+    chrome_android: "18"
+    edge: "12"
+    firefox: "1"
+    firefox_android: "4"
+    safari: "3.1"
+    safari_ios: "2"
+compat_features:
+  # baseline: false
+  # support:
+  #   chrome: "1"
+  #   chrome_android: "18"
+  #   edge: "12"
+  #   firefox: "1"
+  #   firefox_android: "4"
+  #   safari: "1"
+  #   safari_ios: "1"
+  - javascript.builtins.Date.getYear
+  - javascript.builtins.Date.setYear
+  - javascript.builtins.Date.toGMTString
+  - javascript.builtins.String.anchor
+  - javascript.builtins.String.big
+  - javascript.builtins.String.blink
+  - javascript.builtins.String.bold
+  - javascript.builtins.String.fixed
+  - javascript.builtins.String.fontcolor
+  - javascript.builtins.String.fontsize
+  - javascript.builtins.String.italics
+  - javascript.builtins.String.link
+  - javascript.builtins.String.small
+  - javascript.builtins.String.strike
+  - javascript.builtins.String.sub
+  - javascript.builtins.String.substr
+  - javascript.builtins.String.sup
+  - javascript.builtins.escape
+  - javascript.builtins.unescape
+
+  # baseline: false
+  # support:
+  #   chrome: "1"
+  #   chrome_android: "18"
+  #   edge: "12"
+  #   firefox: "1"
+  #   firefox_android: "4"
+  #   safari: "3"
+  #   safari_ios: "1"
+  - javascript.builtins.Object.defineGetter
+  - javascript.builtins.Object.defineSetter
+  - javascript.builtins.Object.lookupGetter
+  - javascript.builtins.Object.lookupSetter
+  - javascript.builtins.Object.proto
+
+  # ⬇️ Same status as overall feature ⬇️
+  # baseline: false
+  # support:
+  #   chrome: "1"
+  #   chrome_android: "18"
+  #   edge: "12"
+  #   firefox: "1"
+  #   firefox_android: "4"
+  #   safari: "3.1"
+  #   safari_ios: "2"
+  - javascript.builtins.RegExp.compile