diff --git a/src/wp-includes/class-wp-theme.php b/src/wp-includes/class-wp-theme.php
index ac04a1c54e..a3c996e59f 100644
--- a/src/wp-includes/class-wp-theme.php
+++ b/src/wp-includes/class-wp-theme.php
@@ -44,6 +44,16 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Default themes.
 	 *
+	 * @since 3.4.0
+	 * @since 3.5.0 Added the Twenty Twelve theme.
+	 * @since 3.6.0 Added the Twenty Thirteen theme.
+	 * @since 3.8.0 Added the Twenty Fourteen theme.
+	 * @since 4.1.0 Added the Twenty Fifteen theme.
+	 * @since 4.4.0 Added the Twenty Sixteen theme.
+	 * @since 4.7.0 Added the Twenty Seventeen theme.
+	 * @since 5.0.0 Added the Twenty Nineteen theme.
+	 * @since 5.3.0 Added the Twenty Twenty theme.
+	 * @since 5.6.0 Added the Twenty Twenty-One theme.
 	 * @var array
 	 */
 	private static $default_themes = array(
@@ -65,6 +75,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Renamed theme tags.
 	 *
+	 * @since 3.8.0
 	 * @var array
 	 */
 	private static $tag_map = array(
@@ -75,6 +86,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Absolute path to the theme root, usually wp-content/themes
 	 *
+	 * @since 3.4.0
 	 * @var string
 	 */
 	private $theme_root;
@@ -82,6 +94,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Header data from the theme's style.css file.
 	 *
+	 * @since 3.4.0
 	 * @var array
 	 */
 	private $headers = array();
@@ -89,6 +102,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Header data from the theme's style.css file after being sanitized.
 	 *
+	 * @since 3.4.0
 	 * @var array
 	 */
 	private $headers_sanitized;
@@ -98,6 +112,7 @@ final class WP_Theme implements ArrayAccess {
 	 *
 	 * Cached due to sorting functions running over the translated name.
 	 *
+	 * @since 3.4.0
 	 * @var string
 	 */
 	private $name_translated;
@@ -105,6 +120,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Errors encountered when initializing the theme.
 	 *
+	 * @since 3.4.0
 	 * @var WP_Error
 	 */
 	private $errors;
@@ -115,6 +131,7 @@ final class WP_Theme implements ArrayAccess {
 	 * In the case of a child theme, this is directory name of the child theme.
 	 * Otherwise, 'stylesheet' is the same as 'template'.
 	 *
+	 * @since 3.4.0
 	 * @var string
 	 */
 	private $stylesheet;
@@ -125,6 +142,7 @@ final class WP_Theme implements ArrayAccess {
 	 * In the case of a child theme, this is the directory name of the parent theme.
 	 * Otherwise, 'template' is the same as 'stylesheet'.
 	 *
+	 * @since 3.4.0
 	 * @var string
 	 */
 	private $template;
@@ -132,6 +150,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * A reference to the parent theme, in the case of a child theme.
 	 *
+	 * @since 3.4.0
 	 * @var WP_Theme
 	 */
 	private $parent;
@@ -139,6 +158,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * URL to the theme root, usually an absolute URL to wp-content/themes
 	 *
+	 * @since 3.4.0
 	 * @var string
 	 */
 	private $theme_root_uri;
@@ -146,6 +166,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Flag for whether the theme's textdomain is loaded.
 	 *
+	 * @since 3.4.0
 	 * @var bool
 	 */
 	private $textdomain_loaded;
@@ -153,6 +174,7 @@ final class WP_Theme implements ArrayAccess {
 	/**
 	 * Stores an md5 hash of the theme root, to function as the cache key.
 	 *
+	 * @since 3.4.0
 	 * @var string
 	 */
 	private $cache_hash;
@@ -162,6 +184,7 @@ final class WP_Theme implements ArrayAccess {
 	 *
 	 * Default is false. Can be set with the {@see 'wp_cache_themes_persistently'} filter.
 	 *
+	 * @since 3.4.0
 	 * @var bool
 	 */
 	private static $persistently_cache;
@@ -171,6 +194,7 @@ final class WP_Theme implements ArrayAccess {
 	 *
 	 * By default the bucket is not cached, so this value is useless.
 	 *
+	 * @since 3.4.0
 	 * @var bool
 	 */
 	private static $cache_expiration = 1800;