From f13685641dd82a41cb84607e845574ff567053ac Mon Sep 17 00:00:00 2001
From: Patrick Brosset <patrick.brosset@microsoft.com>
Date: Wed, 22 Jan 2025 10:23:35 +0100
Subject: [PATCH 01/12] JS discouraged feature

---
 features/javascript-discouraged.yml      | 43 +++++++++++++++
 features/javascript-discouraged.yml.dist | 69 ++++++++++++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 features/javascript-discouraged.yml
 create mode 100644 features/javascript-discouraged.yml.dist

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

From ad8c5d838d22fb16e227e75debf921b0307353f9 Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Mon, 17 Feb 2025 16:18:44 +0100
Subject: [PATCH 02/12] Add discouraged feature for discouraged `escape()` and
 `unescape()`

---
 features/escape-unescape.yml             | 13 +++++++++++++
 features/escape-unescape.yml.dist        | 16 ++++++++++++++++
 features/javascript-discouraged.yml      |  6 ++----
 features/javascript-discouraged.yml.dist |  2 --
 4 files changed, 31 insertions(+), 6 deletions(-)
 create mode 100644 features/escape-unescape.yml
 create mode 100644 features/escape-unescape.yml.dist

diff --git a/features/escape-unescape.yml b/features/escape-unescape.yml
new file mode 100644
index 00000000000..72960745d30
--- /dev/null
+++ b/features/escape-unescape.yml
@@ -0,0 +1,13 @@
+name: escape() and unescape()
+description: The `escape()` and `unescape()` built-in Javascript methods encode and unencode strings using percent encoding, where certain characters are replaced by hexidecimal escape sequences.
+spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-escape-string
+group: javascript
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+  # No `alternatives` becuase it would be `alternatives: [javascript]`. In the
+  # future it'd be nice to have an internal reference to encodeURI(),
+  # decodeURI(), encodeURIComponent(), and decodeURIComponent() instead.
+compat_features:
+  - javascript.builtins.escape
+  - javascript.builtins.unescape
diff --git a/features/escape-unescape.yml.dist b/features/escape-unescape.yml.dist
new file mode 100644
index 00000000000..5e46b0917f2
--- /dev/null
+++ b/features/escape-unescape.yml.dist
@@ -0,0 +1,16 @@
+# Generated from: escape-unescape.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: "1"
+    safari_ios: "1"
+compat_features:
+  - javascript.builtins.escape
+  - javascript.builtins.unescape
diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
index fdaff2570dd..8cdf6d4e0a3 100644
--- a/features/javascript-discouraged.yml
+++ b/features/javascript-discouraged.yml
@@ -1,5 +1,5 @@
 name: JavaScript built-ins (legacy)
-description: 
+description: [This feature is being decomposed.]
 spec: https://tc39.es/ecma262/multipage/
 group: javascript
 discouraged:
@@ -10,8 +10,6 @@ discouraged:
 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
@@ -40,4 +38,4 @@ compat_features:
 
   # 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
+  - javascript.builtins.Object.proto
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
index ca1e072ba9a..bdb9b12a0a8 100644
--- a/features/javascript-discouraged.yml.dist
+++ b/features/javascript-discouraged.yml.dist
@@ -38,8 +38,6 @@ compat_features:
   - javascript.builtins.String.sub
   - javascript.builtins.String.substr
   - javascript.builtins.String.sup
-  - javascript.builtins.escape
-  - javascript.builtins.unescape
 
   # baseline: false
   # support:

From f052c4fb64cce8fc914abcd8c3ef5e60d804c75d Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Mon, 17 Feb 2025 17:41:16 +0100
Subject: [PATCH 03/12] Add discouraged HTML wrapper methods feature

---
 features/html-wrapper-methods.yml        | 24 ++++++++++++++++++++
 features/html-wrapper-methods.yml.dist   | 28 ++++++++++++++++++++++++
 features/javascript-discouraged.yml      | 14 ------------
 features/javascript-discouraged.yml.dist | 14 ------------
 4 files changed, 52 insertions(+), 28 deletions(-)
 create mode 100644 features/html-wrapper-methods.yml
 create mode 100644 features/html-wrapper-methods.yml.dist

diff --git a/features/html-wrapper-methods.yml b/features/html-wrapper-methods.yml
new file mode 100644
index 00000000000..45ac41987f9
--- /dev/null
+++ b/features/html-wrapper-methods.yml
@@ -0,0 +1,24 @@
+name: HTML wrapper methods
+description: JavaScript built-in methods such as, `String.bold()` and `String.italics()`, wrap strings in (often historic) HTML.
+spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-properties-of-the-string.prototype-object
+group: javascript
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+  alternatives:
+    - dom
+compat_features:
+  - 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
diff --git a/features/html-wrapper-methods.yml.dist b/features/html-wrapper-methods.yml.dist
new file mode 100644
index 00000000000..a4c6ea216c9
--- /dev/null
+++ b/features/html-wrapper-methods.yml.dist
@@ -0,0 +1,28 @@
+# Generated from: html-wrapper-methods.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: "1"
+    safari_ios: "1"
+compat_features:
+  - 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
diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
index 8cdf6d4e0a3..07783db8f35 100644
--- a/features/javascript-discouraged.yml
+++ b/features/javascript-discouraged.yml
@@ -10,20 +10,6 @@ discouraged:
 compat_features:
   # The following properties are legacy according to:
   # https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
-  - 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
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
index bdb9b12a0a8..18eac033b70 100644
--- a/features/javascript-discouraged.yml.dist
+++ b/features/javascript-discouraged.yml.dist
@@ -24,20 +24,6 @@ compat_features:
   - 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
 
   # baseline: false
   # support:

From 8ff33f6380c885104bb36a7e91e95a85f3ae7b0c Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Mon, 17 Feb 2025 17:51:57 +0100
Subject: [PATCH 04/12] Add discouraged feature for
 `Date.prototype.{get,set}Year()`

---
 features/date-get-year-set-year.yml      | 13 +++++++++++++
 features/date-get-year-set-year.yml.dist | 16 ++++++++++++++++
 features/javascript-discouraged.yml      |  2 --
 features/javascript-discouraged.yml.dist |  2 --
 4 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 features/date-get-year-set-year.yml
 create mode 100644 features/date-get-year-set-year.yml.dist

diff --git a/features/date-get-year-set-year.yml b/features/date-get-year-set-year.yml
new file mode 100644
index 00000000000..5d7c1e934de
--- /dev/null
+++ b/features/date-get-year-set-year.yml
@@ -0,0 +1,13 @@
+name: getYear() and setYear()
+description: The `getYear()` and `setYear()` methods of `Date` objects get and set the year offset to 1900, changing a date's year in way that is subject to the year 2000 problem.
+spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-date.prototype.getyear
+group: javascript
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+  # No `alternatives` becuase it would be `alternatives: [date]`. In the future
+  # it'd be nice to have an internal reference to getFullYear() and
+  # setFullYear() instead.
+compat_features:
+  - javascript.builtins.Date.getYear
+  - javascript.builtins.Date.setYear
diff --git a/features/date-get-year-set-year.yml.dist b/features/date-get-year-set-year.yml.dist
new file mode 100644
index 00000000000..e99853bb88a
--- /dev/null
+++ b/features/date-get-year-set-year.yml.dist
@@ -0,0 +1,16 @@
+# Generated from: date-get-year-set-year.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: "1"
+    safari_ios: "1"
+compat_features:
+  - javascript.builtins.Date.getYear
+  - javascript.builtins.Date.setYear
diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
index 07783db8f35..93ab1654301 100644
--- a/features/javascript-discouraged.yml
+++ b/features/javascript-discouraged.yml
@@ -10,8 +10,6 @@ discouraged:
 compat_features:
   # The following properties are legacy according to:
   # https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
-  - javascript.builtins.Date.getYear
-  - javascript.builtins.Date.setYear
   - javascript.builtins.Date.toGMTString
   - javascript.builtins.RegExp.compile
 
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
index 18eac033b70..5155813e6ef 100644
--- a/features/javascript-discouraged.yml.dist
+++ b/features/javascript-discouraged.yml.dist
@@ -21,8 +21,6 @@ compat_features:
   #   firefox_android: "4"
   #   safari: "1"
   #   safari_ios: "1"
-  - javascript.builtins.Date.getYear
-  - javascript.builtins.Date.setYear
   - javascript.builtins.Date.toGMTString
 
   # baseline: false

From 5e32efdf2a294c3f37dc3b7b1a71cc7b0a4b504b Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Mon, 17 Feb 2025 18:05:55 +0100
Subject: [PATCH 05/12] Add discouraged feature for getter and setter defining
 methods

---
 features/accessor-methods.yml            | 15 +++++++++++++++
 features/accessor-methods.yml.dist       | 18 ++++++++++++++++++
 features/javascript-discouraged.yml      |  7 -------
 features/javascript-discouraged.yml.dist |  4 ----
 4 files changed, 33 insertions(+), 11 deletions(-)
 create mode 100644 features/accessor-methods.yml
 create mode 100644 features/accessor-methods.yml.dist

diff --git a/features/accessor-methods.yml b/features/accessor-methods.yml
new file mode 100644
index 00000000000..a53b2b277ae
--- /dev/null
+++ b/features/accessor-methods.yml
@@ -0,0 +1,15 @@
+name: Accessor methods
+description: The `__defineGetter__()` and `__defineSetter__()` methods of objects bind a function to a property, which is called on setting or reading the property.
+spec: https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.prototype-legacy-accessor-methods
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+    # No `alternatives` becuase it would be `alternatives:
+    # [object-object, functions]`. In the future it'd be nice to have an
+    # internal reference to the object defineProperty method and the function
+    # get/set syntax.
+compat_features:
+  - javascript.builtins.Object.defineGetter
+  - javascript.builtins.Object.defineSetter
+  - javascript.builtins.Object.lookupGetter
+  - javascript.builtins.Object.lookupSetter
diff --git a/features/accessor-methods.yml.dist b/features/accessor-methods.yml.dist
new file mode 100644
index 00000000000..179d572c0a9
--- /dev/null
+++ b/features/accessor-methods.yml.dist
@@ -0,0 +1,18 @@
+# Generated from: accessor-methods.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"
+    safari_ios: "1"
+compat_features:
+  - javascript.builtins.Object.defineGetter
+  - javascript.builtins.Object.defineSetter
+  - javascript.builtins.Object.lookupGetter
+  - javascript.builtins.Object.lookupSetter
diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
index 93ab1654301..ff2924838a1 100644
--- a/features/javascript-discouraged.yml
+++ b/features/javascript-discouraged.yml
@@ -13,13 +13,6 @@ compat_features:
   - 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
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
index 5155813e6ef..ab1db5ffe28 100644
--- a/features/javascript-discouraged.yml.dist
+++ b/features/javascript-discouraged.yml.dist
@@ -32,10 +32,6 @@ compat_features:
   #   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 ⬇️

From a429475e2abe9d99dcb404555712a2c50b2f9031 Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Tue, 18 Feb 2025 12:57:57 +0100
Subject: [PATCH 06/12] Add discouraged feature for `__proto__`

---
 features/javascript-discouraged.yml      |  4 ----
 features/javascript-discouraged.yml.dist | 11 -----------
 features/proto.yml                       | 11 +++++++++++
 features/proto.yml.dist                  | 15 +++++++++++++++
 4 files changed, 26 insertions(+), 15 deletions(-)
 create mode 100644 features/proto.yml
 create mode 100644 features/proto.yml.dist

diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
index ff2924838a1..ed024790698 100644
--- a/features/javascript-discouraged.yml
+++ b/features/javascript-discouraged.yml
@@ -12,7 +12,3 @@ compat_features:
   # https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
   - javascript.builtins.Date.toGMTString
   - javascript.builtins.RegExp.compile
-
-  # The following properties are legacy according to:
-  # https://tc39.es/ecma262/#sec-object.prototype.__proto__
-  - javascript.builtins.Object.proto
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
index ab1db5ffe28..44bb46660c9 100644
--- a/features/javascript-discouraged.yml.dist
+++ b/features/javascript-discouraged.yml.dist
@@ -23,17 +23,6 @@ compat_features:
   #   safari_ios: "1"
   - javascript.builtins.Date.toGMTString
 
-  # baseline: false
-  # support:
-  #   chrome: "1"
-  #   chrome_android: "18"
-  #   edge: "12"
-  #   firefox: "1"
-  #   firefox_android: "4"
-  #   safari: "3"
-  #   safari_ios: "1"
-  - javascript.builtins.Object.proto
-
   # ⬇️ Same status as overall feature ⬇️
   # baseline: false
   # support:
diff --git a/features/proto.yml b/features/proto.yml
new file mode 100644
index 00000000000..b66360ded69
--- /dev/null
+++ b/features/proto.yml
@@ -0,0 +1,11 @@
+name: __proto__
+description: The `__proto__` property of objects partially exposes the prototype of an object.
+spec: https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.prototype.__proto__
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+  # No `alternatives` becuase it would be `alternatives: [object]`. In the
+  # future it'd be nice to have an internal reference to `getPrototypeOf()` and
+  # `setPrototypeOf()` instead.
+compat_features:
+  - javascript.builtins.Object.proto
diff --git a/features/proto.yml.dist b/features/proto.yml.dist
new file mode 100644
index 00000000000..8def5e653c7
--- /dev/null
+++ b/features/proto.yml.dist
@@ -0,0 +1,15 @@
+# Generated from: proto.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"
+    safari_ios: "1"
+compat_features:
+  - javascript.builtins.Object.proto

From 1f02a0560dc0111ce4721324fdbcbfc6ad6ce354 Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Tue, 18 Feb 2025 13:05:42 +0100
Subject: [PATCH 07/12] Add discouraged feature for the `RegExp` `compile()`
 method

---
 features/javascript-discouraged.yml |  3 +--
 features/regexp-compile.yml         | 11 +++++++++++
 features/regexp-compile.yml.dist    | 15 +++++++++++++++
 3 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 features/regexp-compile.yml
 create mode 100644 features/regexp-compile.yml.dist

diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
index ed024790698..8d4d6a2169c 100644
--- a/features/javascript-discouraged.yml
+++ b/features/javascript-discouraged.yml
@@ -10,5 +10,4 @@ discouraged:
 compat_features:
   # The following properties are legacy according to:
   # https://tc39.es/ecma262/#sec-additional-ecmascript-features-for-web-browsers
-  - javascript.builtins.Date.toGMTString
-  - javascript.builtins.RegExp.compile
+  - javascript.builtins.Date.toGMTString
\ No newline at end of file
diff --git a/features/regexp-compile.yml b/features/regexp-compile.yml
new file mode 100644
index 00000000000..324e0c29f00
--- /dev/null
+++ b/features/regexp-compile.yml
@@ -0,0 +1,11 @@
+name: RegExp compile()
+description: The `compile()` method of `RegExp` objects recompiles an existing regular expression object using a new pattern and flags.
+spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-regexp.prototype.compile
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+  # No `alternatives` becuase it would be `alternatives: [regexp]`. In the
+  # future it'd be nice to have an internal reference to the RegExp()
+  # constructor instead.
+compat_features:
+  - javascript.builtins.RegExp.compile
diff --git a/features/regexp-compile.yml.dist b/features/regexp-compile.yml.dist
new file mode 100644
index 00000000000..871d9e763f6
--- /dev/null
+++ b/features/regexp-compile.yml.dist
@@ -0,0 +1,15 @@
+# Generated from: regexp-compile.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:
+  - javascript.builtins.RegExp.compile

From f9000431c0868d9677908f85adb2ef7237cdb0ab Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Tue, 18 Feb 2025 13:12:40 +0100
Subject: [PATCH 08/12] Add discouraged feature for `toGMTString()` method

---
 features/date-to-gmt-string.yml          | 11 ++++++++
 features/date-to-gmt-string.yml.dist     | 15 ++++++++++
 features/javascript-discouraged.yml      | 13 ---------
 features/javascript-discouraged.yml.dist | 36 ------------------------
 4 files changed, 26 insertions(+), 49 deletions(-)
 create mode 100644 features/date-to-gmt-string.yml
 create mode 100644 features/date-to-gmt-string.yml.dist
 delete mode 100644 features/javascript-discouraged.yml
 delete mode 100644 features/javascript-discouraged.yml.dist

diff --git a/features/date-to-gmt-string.yml b/features/date-to-gmt-string.yml
new file mode 100644
index 00000000000..ad02d41fca7
--- /dev/null
+++ b/features/date-to-gmt-string.yml
@@ -0,0 +1,11 @@
+name: toGMTString()
+description: The `toGMTSTring()` method of `Date` objects is an alias to the `toUTCString()` method.
+spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-date.prototype.togmtstring
+discouraged:
+  according_to:
+    - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
+  # No `alternatives` becuase it would be `alternatives: [date]`. In the future
+  # it'd be nice to have an internal reference to the `toUTCString()` method
+  # instead.
+compat_features:
+  - javascript.builtins.Date.toGMTString
diff --git a/features/date-to-gmt-string.yml.dist b/features/date-to-gmt-string.yml.dist
new file mode 100644
index 00000000000..b4f246110ed
--- /dev/null
+++ b/features/date-to-gmt-string.yml.dist
@@ -0,0 +1,15 @@
+# Generated from: date-to-gmt-string.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: "1"
+    safari_ios: "1"
+compat_features:
+  - javascript.builtins.Date.toGMTString
diff --git a/features/javascript-discouraged.yml b/features/javascript-discouraged.yml
deleted file mode 100644
index 8d4d6a2169c..00000000000
--- a/features/javascript-discouraged.yml
+++ /dev/null
@@ -1,13 +0,0 @@
-name: JavaScript built-ins (legacy)
-description: [This feature is being decomposed.]
-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.Date.toGMTString
\ No newline at end of file
diff --git a/features/javascript-discouraged.yml.dist b/features/javascript-discouraged.yml.dist
deleted file mode 100644
index 44bb46660c9..00000000000
--- a/features/javascript-discouraged.yml.dist
+++ /dev/null
@@ -1,36 +0,0 @@
-# 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.toGMTString
-
-  # ⬇️ 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

From a969a021e3ccbdb0df3286753909343b61dd8000 Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Thu, 20 Feb 2025 14:59:27 +0100
Subject: [PATCH 09/12] Fix typos

---
 features/accessor-methods.yml       | 2 +-
 features/date-get-year-set-year.yml | 2 +-
 features/date-to-gmt-string.yml     | 2 +-
 features/escape-unescape.yml        | 2 +-
 features/proto.yml                  | 2 +-
 features/regexp-compile.yml         | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/features/accessor-methods.yml b/features/accessor-methods.yml
index a53b2b277ae..5540d76782c 100644
--- a/features/accessor-methods.yml
+++ b/features/accessor-methods.yml
@@ -4,7 +4,7 @@ spec: https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.prot
 discouraged:
   according_to:
     - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
-    # No `alternatives` becuase it would be `alternatives:
+    # No `alternatives` because it would be `alternatives:
     # [object-object, functions]`. In the future it'd be nice to have an
     # internal reference to the object defineProperty method and the function
     # get/set syntax.
diff --git a/features/date-get-year-set-year.yml b/features/date-get-year-set-year.yml
index 5d7c1e934de..10a6f299aae 100644
--- a/features/date-get-year-set-year.yml
+++ b/features/date-get-year-set-year.yml
@@ -5,7 +5,7 @@ group: javascript
 discouraged:
   according_to:
     - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
-  # No `alternatives` becuase it would be `alternatives: [date]`. In the future
+  # No `alternatives` because it would be `alternatives: [date]`. In the future
   # it'd be nice to have an internal reference to getFullYear() and
   # setFullYear() instead.
 compat_features:
diff --git a/features/date-to-gmt-string.yml b/features/date-to-gmt-string.yml
index ad02d41fca7..4bc516ff03f 100644
--- a/features/date-to-gmt-string.yml
+++ b/features/date-to-gmt-string.yml
@@ -4,7 +4,7 @@ spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-b
 discouraged:
   according_to:
     - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
-  # No `alternatives` becuase it would be `alternatives: [date]`. In the future
+  # No `alternatives` because it would be `alternatives: [date]`. In the future
   # it'd be nice to have an internal reference to the `toUTCString()` method
   # instead.
 compat_features:
diff --git a/features/escape-unescape.yml b/features/escape-unescape.yml
index 72960745d30..7189404faa6 100644
--- a/features/escape-unescape.yml
+++ b/features/escape-unescape.yml
@@ -5,7 +5,7 @@ group: javascript
 discouraged:
   according_to:
     - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
-  # No `alternatives` becuase it would be `alternatives: [javascript]`. In the
+  # No `alternatives` because it would be `alternatives: [javascript]`. In the
   # future it'd be nice to have an internal reference to encodeURI(),
   # decodeURI(), encodeURIComponent(), and decodeURIComponent() instead.
 compat_features:
diff --git a/features/proto.yml b/features/proto.yml
index b66360ded69..220215e564a 100644
--- a/features/proto.yml
+++ b/features/proto.yml
@@ -4,7 +4,7 @@ spec: https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.prot
 discouraged:
   according_to:
     - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
-  # No `alternatives` becuase it would be `alternatives: [object]`. In the
+  # No `alternatives` because it would be `alternatives: [object]`. In the
   # future it'd be nice to have an internal reference to `getPrototypeOf()` and
   # `setPrototypeOf()` instead.
 compat_features:
diff --git a/features/regexp-compile.yml b/features/regexp-compile.yml
index 324e0c29f00..029ef2b1107 100644
--- a/features/regexp-compile.yml
+++ b/features/regexp-compile.yml
@@ -4,7 +4,7 @@ spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-b
 discouraged:
   according_to:
     - https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-additional-ecmascript-features-for-web-browsers
-  # No `alternatives` becuase it would be `alternatives: [regexp]`. In the
+  # No `alternatives` because it would be `alternatives: [regexp]`. In the
   # future it'd be nice to have an internal reference to the RegExp()
   # constructor instead.
 compat_features:

From 7ee30da142ac176c47c84a6f95b564112aae428b Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Thu, 20 Feb 2025 15:00:45 +0100
Subject: [PATCH 10/12] Cross-reference issue about feature subsetting for
 alternatives

https://github.com/web-platform-dx/web-features/issues/2676
---
 features/accessor-methods.yml       | 1 +
 features/date-get-year-set-year.yml | 1 +
 features/date-to-gmt-string.yml     | 1 +
 features/escape-unescape.yml        | 1 +
 features/proto.yml                  | 1 +
 features/regexp-compile.yml         | 1 +
 6 files changed, 6 insertions(+)

diff --git a/features/accessor-methods.yml b/features/accessor-methods.yml
index 5540d76782c..133090d4936 100644
--- a/features/accessor-methods.yml
+++ b/features/accessor-methods.yml
@@ -8,6 +8,7 @@ discouraged:
     # [object-object, functions]`. In the future it'd be nice to have an
     # internal reference to the object defineProperty method and the function
     # get/set syntax.
+    # See https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.Object.defineGetter
   - javascript.builtins.Object.defineSetter
diff --git a/features/date-get-year-set-year.yml b/features/date-get-year-set-year.yml
index 10a6f299aae..8c5609e8887 100644
--- a/features/date-get-year-set-year.yml
+++ b/features/date-get-year-set-year.yml
@@ -8,6 +8,7 @@ discouraged:
   # No `alternatives` because it would be `alternatives: [date]`. In the future
   # it'd be nice to have an internal reference to getFullYear() and
   # setFullYear() instead.
+  # See: https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.Date.getYear
   - javascript.builtins.Date.setYear
diff --git a/features/date-to-gmt-string.yml b/features/date-to-gmt-string.yml
index 4bc516ff03f..ffc9335c809 100644
--- a/features/date-to-gmt-string.yml
+++ b/features/date-to-gmt-string.yml
@@ -7,5 +7,6 @@ discouraged:
   # No `alternatives` because it would be `alternatives: [date]`. In the future
   # it'd be nice to have an internal reference to the `toUTCString()` method
   # instead.
+  # See: https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.Date.toGMTString
diff --git a/features/escape-unescape.yml b/features/escape-unescape.yml
index 7189404faa6..5ac841c28b9 100644
--- a/features/escape-unescape.yml
+++ b/features/escape-unescape.yml
@@ -8,6 +8,7 @@ discouraged:
   # No `alternatives` because it would be `alternatives: [javascript]`. In the
   # future it'd be nice to have an internal reference to encodeURI(),
   # decodeURI(), encodeURIComponent(), and decodeURIComponent() instead.
+  # See: https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.escape
   - javascript.builtins.unescape
diff --git a/features/proto.yml b/features/proto.yml
index 220215e564a..6315909a6b1 100644
--- a/features/proto.yml
+++ b/features/proto.yml
@@ -7,5 +7,6 @@ discouraged:
   # No `alternatives` because it would be `alternatives: [object]`. In the
   # future it'd be nice to have an internal reference to `getPrototypeOf()` and
   # `setPrototypeOf()` instead.
+  # See: https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.Object.proto
diff --git a/features/regexp-compile.yml b/features/regexp-compile.yml
index 029ef2b1107..f363a0776b7 100644
--- a/features/regexp-compile.yml
+++ b/features/regexp-compile.yml
@@ -7,5 +7,6 @@ discouraged:
   # No `alternatives` because it would be `alternatives: [regexp]`. In the
   # future it'd be nice to have an internal reference to the RegExp()
   # constructor instead.
+  # See: https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.RegExp.compile

From 4a1041d3aebeeeca21dae999df27db2f1f0e084c Mon Sep 17 00:00:00 2001
From: "Daniel D. Beck" <daniel@ddbeck.com>
Date: Thu, 20 Feb 2025 15:11:15 +0100
Subject: [PATCH 11/12] Add missing link

---
 features/accessor-methods.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/features/accessor-methods.yml b/features/accessor-methods.yml
index 133090d4936..239ae0eff1a 100644
--- a/features/accessor-methods.yml
+++ b/features/accessor-methods.yml
@@ -8,7 +8,7 @@ discouraged:
     # [object-object, functions]`. In the future it'd be nice to have an
     # internal reference to the object defineProperty method and the function
     # get/set syntax.
-    # See https://github.com/web-platform-dx/web-features/issues/2676
+    # See: https://github.com/web-platform-dx/web-features/issues/2676
 compat_features:
   - javascript.builtins.Object.defineGetter
   - javascript.builtins.Object.defineSetter

From 117674f753a19dbebcdf56652f814efe3eb1fd7f Mon Sep 17 00:00:00 2001
From: Patrick Brosset <patrickbrosset@gmail.com>
Date: Sat, 1 Mar 2025 09:03:13 +0100
Subject: [PATCH 12/12] Update date-get-year-set-year.yml

Co-authored-by: Daniel D. Beck <daniel@ddbeck.com>
---
 features/date-get-year-set-year.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/features/date-get-year-set-year.yml b/features/date-get-year-set-year.yml
index 8c5609e8887..bfed0819dd1 100644
--- a/features/date-get-year-set-year.yml
+++ b/features/date-get-year-set-year.yml
@@ -1,5 +1,5 @@
 name: getYear() and setYear()
-description: The `getYear()` and `setYear()` methods of `Date` objects get and set the year offset to 1900, changing a date's year in way that is subject to the year 2000 problem.
+description: The `getYear()` and `setYear()` methods of `Date` objects get and set the year as an offset to 1900.
 spec: https://tc39.es/ecma262/multipage/additional-ecmascript-features-for-web-browsers.html#sec-date.prototype.getyear
 group: javascript
 discouraged: