[BUGFIX lts] Correct documentation for deprecation of EXTEND_PROTOTYPES

Author: kategengler

packages/@ember/-internals/environment/lib/env.ts

@@ -20,19 +20,14 @@ export const ENV = {
     native object prototypes, a few extra methods in order to provide a more
     friendly API.
 
-    We generally recommend leaving this option set to true however, if you need
-    to turn it off, you can add the configuration property
-    `EXTEND_PROTOTYPES` to `EmberENV` and set it to `false`.
-
-    Note, when disabled (the default configuration for Ember Addons), you will
-    instead have to access all methods and functions from the Ember
-    namespace.
+    The behavior from setting this option to `true` was deprecated in Ember 5.10.
 
     @property EXTEND_PROTOTYPES
     @type Boolean
     @default true
     @for EmberENV
     @public
+    @deprecated in v5.10
   */
   EXTEND_PROTOTYPES: {
     Array: true,
@@ -201,6 +196,9 @@ export const ENV = {
     }
   }
 
+  // TODO: Remove in Ember 6.5. This setting code for EXTEND_PROTOTYPES
+  // should stay for at least an LTS cycle so that users get the explicit
+  // deprecation exception when it breaks in >= 6.0.0.
   let { EXTEND_PROTOTYPES } = EmberENV;
   if (EXTEND_PROTOTYPES !== undefined) {
     if (typeof EXTEND_PROTOTYPES === 'object' && EXTEND_PROTOTYPES !== null) {

packages/@ember/array/index.ts

@@ -1858,11 +1858,7 @@ const MutableArray = Mixin.create(EmberArray, MutableEnumerable, {
 
 /**
   Creates an `Ember.NativeArray` from an Array-like object.
-  Does not modify the original object's contents. `A()` is not needed if
-  `EmberENV.EXTEND_PROTOTYPES` is `true` (the default value). However,
-  it is recommended that you use `A()` when creating addons for
-  ember or when you can not guarantee that `EmberENV.EXTEND_PROTOTYPES`
-  will be `true`.
+  Does not modify the original object's contents.
 
   Example
 
@@ -2061,10 +2057,7 @@ interface MutableArrayWithoutNative<T>
 
 /**
   The NativeArray mixin contains the properties needed to make the native
-  Array support MutableArray and all of its dependent APIs. Unless you
-  have `EmberENV.EXTEND_PROTOTYPES` or `EmberENV.EXTEND_PROTOTYPES.Array` set to
-  false, this will be applied automatically. Otherwise you can apply the mixin
-  at anytime by calling `Ember.NativeArray.apply(Array.prototype)`.
+  Array support MutableArray and all of its dependent APIs.
 
   @class Ember.NativeArray
   @uses MutableArray