diff --git src/index.php src/index.php
index 91c0517857..027df0affc 100644
--- src/index.php
+++ src/index.php
@@ -4,6 +4,8 @@
  * Note: this file exists only to remind developers to build the assets.
  * For the real index.php that gets built and boots WordPress,
  * please refer to _index.php.
+ *
+ * @package WordPress
  */
 
 /** Define ABSPATH as this file's directory */
diff --git src/wp-admin/index.php src/wp-admin/index.php
index 628096844c..af687f7bbe 100644
--- src/wp-admin/index.php
+++ src/wp-admin/index.php
@@ -1,9 +1,10 @@
 <?php
-
-/*
+/**
  * Note: this file exists only to remind developers to build the assets.
  * For the real wp-admin/index.php that gets built and boots WordPress,
  * please refer to wp-admin/_index.php.
+ *
+ * @package WordPress
  */
 
 if ( file_exists( __DIR__ . '/../wp-includes/js/dist/edit-post.js' ) ) {
diff --git src/wp-admin/load-scripts.php src/wp-admin/load-scripts.php
index e4b6a1ee5b..934fc79b0c 100644
--- src/wp-admin/load-scripts.php
+++ src/wp-admin/load-scripts.php
@@ -1,10 +1,12 @@
 <?php
-
-/*
+/**
  * The error_reporting() function can be disabled in php.ini. On systems where that is the case,
  * it's best to add a dummy function to the wp-config.php file, but as this call to the function
  * is run prior to wp-config.php loading, it is wrapped in a function_exists() check.
+ *
+ * @package WordPress
  */
+
 if ( function_exists( 'error_reporting' ) ) {
 	/*
 	 * Disable error reporting.
diff --git src/wp-admin/load-styles.php src/wp-admin/load-styles.php
index 3bdfcc7a22..177c2757f8 100644
--- src/wp-admin/load-styles.php
+++ src/wp-admin/load-styles.php
@@ -1,10 +1,12 @@
 <?php
-
-/*
+/**
  * The error_reporting() function can be disabled in php.ini. On systems where that is the case,
  * it's best to add a dummy function to the wp-config.php file, but as this call to the function
  * is run prior to wp-config.php loading, it is wrapped in a function_exists() check.
+ *
+ * @package WordPress
  */
+
 if ( function_exists( 'error_reporting' ) ) {
 	/*
 	 * Disable error reporting.
diff --git src/wp-includes/class-phpass.php src/wp-includes/class-phpass.php
index f8f659648e..27598001f3 100644
--- src/wp-includes/class-phpass.php
+++ src/wp-includes/class-phpass.php
@@ -1,6 +1,7 @@
 <?php
 /**
  * Portable PHP password hashing framework.
+ *
  * @package phpass
  * @since 2.5.0
  * @version 0.5 / WordPress
diff --git src/wp-includes/class-phpmailer.php src/wp-includes/class-phpmailer.php
index fe054f6879..e2b8e11383 100644
--- src/wp-includes/class-phpmailer.php
+++ src/wp-includes/class-phpmailer.php
@@ -1,8 +1,10 @@
 <?php
-
 /**
  * The PHPMailer class has been moved to the wp-includes/PHPMailer subdirectory and now uses the PHPMailer\PHPMailer namespace.
+ *
+ * @package phpmailer
  */
+
 if ( function_exists( '_deprecated_file' ) ) {
 	_deprecated_file(
 		basename( __FILE__ ),
diff --git src/wp-includes/class-smtp.php src/wp-includes/class-smtp.php
index 524e655250..36cfd8a968 100644
--- src/wp-includes/class-smtp.php
+++ src/wp-includes/class-smtp.php
@@ -1,8 +1,10 @@
 <?php
-
 /**
  * The SMTP class has been moved to the wp-includes/PHPMailer subdirectory and now uses the PHPMailer\PHPMailer namespace.
+ *
+ * @package smtp
  */
+
 _deprecated_file(
 	basename( __FILE__ ),
 	'5.5.0',
diff --git src/wp-includes/class-snoopy.php src/wp-includes/class-snoopy.php
index e82c673989..612e481fe9 100644
--- src/wp-includes/class-snoopy.php
+++ src/wp-includes/class-snoopy.php
@@ -1,8 +1,10 @@
 <?php
-
 /**
  * Deprecated. Use WP_HTTP (http.php) instead.
+ *
+ * @package snoopy
  */
+
 _deprecated_file( basename( __FILE__ ), '3.0.0', WPINC . '/http.php' );
 
 if ( ! class_exists( 'Snoopy', false ) ) :
diff --git src/wp-includes/class-wp-oembed-controller.php src/wp-includes/class-wp-oembed-controller.php
index d78a76d885..e09ac93051 100644
--- src/wp-includes/class-wp-oembed-controller.php
+++ src/wp-includes/class-wp-oembed-controller.php
@@ -8,7 +8,7 @@
  */
 
 /**
- * oEmbed API endpoint controller.
+ * OEmbed API endpoint controller.
  *
  * Registers the REST API route and delivers the response data.
  * The output format (XML or JSON) is handled by the REST API.
diff --git src/wp-includes/embed.php src/wp-includes/embed.php
index f7fe10e482..5b952ef774 100644
--- src/wp-includes/embed.php
+++ src/wp-includes/embed.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * oEmbed API: Top-level oEmbed functionality
+ * Oembed API: Top-level oEmbed functionality
  *
  * @package WordPress
  * @subpackage oEmbed
diff --git src/wp-includes/pluggable-deprecated.php src/wp-includes/pluggable-deprecated.php
index 11e393ddfd..3ac612b6d2 100644
--- src/wp-includes/pluggable-deprecated.php
+++ src/wp-includes/pluggable-deprecated.php
@@ -15,171 +15,171 @@
  * Deprecated functions come here to die.
  */
 
-if ( !function_exists('set_current_user') ) :
-/**
- * Changes the current user by ID or name.
- *
- * Set $id to null and specify a name if you do not know a user's ID.
- *
- * @since 2.0.1
- * @deprecated 3.0.0 Use wp_set_current_user()
- * @see wp_set_current_user()
- *
- * @param int|null $id User ID.
- * @param string $name Optional. The user's username
- * @return WP_User returns wp_set_current_user()
- */
-function set_current_user($id, $name = '') {
-	_deprecated_function( __FUNCTION__, '3.0.0', 'wp_set_current_user()' );
-	return wp_set_current_user($id, $name);
-}
+if ( ! function_exists('set_current_user') ) :
+	/**
+	 * Changes the current user by ID or name.
+	 *
+	 * Set $id to null and specify a name if you do not know a user's ID.
+	 *
+	 * @since 2.0.1
+	 * @deprecated 3.0.0 Use wp_set_current_user()
+	 * @see wp_set_current_user()
+	 *
+	 * @param int|null $id User ID.
+	 * @param string $name Optional. The user's username
+	 * @return WP_User returns wp_set_current_user()
+	 */
+	function set_current_user($id, $name = '') {
+		_deprecated_function( __FUNCTION__, '3.0.0', 'wp_set_current_user()' );
+		return wp_set_current_user($id, $name);
+	}
 endif;
 
-if ( !function_exists('get_currentuserinfo') ) :
-/**
- * Populate global variables with information about the currently logged in user.
- *
- * @since 0.71
- * @deprecated 4.5.0 Use wp_get_current_user()
- * @see wp_get_current_user()
- *
- * @return bool|WP_User False on XMLRPC Request and invalid auth cookie, WP_User instance otherwise.
- */
-function get_currentuserinfo() {
-	_deprecated_function( __FUNCTION__, '4.5.0', 'wp_get_current_user()' );
+if ( ! function_exists('get_currentuserinfo') ) :
+	/**
+	 * Populate global variables with information about the currently logged in user.
+	 *
+	 * @since 0.71
+	 * @deprecated 4.5.0 Use wp_get_current_user()
+	 * @see wp_get_current_user()
+	 *
+	 * @return bool|WP_User False on XMLRPC Request and invalid auth cookie, WP_User instance otherwise.
+	 */
+	function get_currentuserinfo() {
+		_deprecated_function( __FUNCTION__, '4.5.0', 'wp_get_current_user()' );
 
-	return _wp_get_current_user();
-}
+		return _wp_get_current_user();
+	}
 endif;
 
-if ( !function_exists('get_userdatabylogin') ) :
-/**
- * Retrieve user info by login name.
- *
- * @since 0.71
- * @deprecated 3.3.0 Use get_user_by()
- * @see get_user_by()
- *
- * @param string $user_login User's username
- * @return bool|object False on failure, User DB row object
- */
-function get_userdatabylogin($user_login) {
-	_deprecated_function( __FUNCTION__, '3.3.0', "get_user_by('login')" );
-	return get_user_by('login', $user_login);
-}
+if ( ! function_exists('get_userdatabylogin') ) :
+	/**
+	 * Retrieve user info by login name.
+	 *
+	 * @since 0.71
+	 * @deprecated 3.3.0 Use get_user_by()
+	 * @see get_user_by()
+	 *
+	 * @param string $user_login User's username
+	 * @return bool|object False on failure, User DB row object
+	 */
+	function get_userdatabylogin($user_login) {
+		_deprecated_function( __FUNCTION__, '3.3.0', "get_user_by('login')" );
+		return get_user_by('login', $user_login);
+	}
 endif;
 
-if ( !function_exists('get_user_by_email') ) :
-/**
- * Retrieve user info by email.
- *
- * @since 2.5.0
- * @deprecated 3.3.0 Use get_user_by()
- * @see get_user_by()
- *
- * @param string $email User's email address
- * @return bool|object False on failure, User DB row object
- */
-function get_user_by_email($email) {
-	_deprecated_function( __FUNCTION__, '3.3.0', "get_user_by('email')" );
-	return get_user_by('email', $email);
-}
+if ( ! function_exists('get_user_by_email') ) :
+	/**
+	 * Retrieve user info by email.
+	 *
+	 * @since 2.5.0
+	 * @deprecated 3.3.0 Use get_user_by()
+	 * @see get_user_by()
+	 *
+	 * @param string $email User's email address
+	 * @return bool|object False on failure, User DB row object
+	 */
+	function get_user_by_email($email) {
+		_deprecated_function( __FUNCTION__, '3.3.0', "get_user_by('email')" );
+		return get_user_by('email', $email);
+	}
 endif;
 
-if ( !function_exists('wp_setcookie') ) :
-/**
- * Sets a cookie for a user who just logged in. This function is deprecated.
- *
- * @since 1.5.0
- * @deprecated 2.5.0 Use wp_set_auth_cookie()
- * @see wp_set_auth_cookie()
- *
- * @param string $username The user's username
- * @param string $password Optional. The user's password
- * @param bool $already_md5 Optional. Whether the password has already been through MD5
- * @param string $home Optional. Will be used instead of COOKIEPATH if set
- * @param string $siteurl Optional. Will be used instead of SITECOOKIEPATH if set
- * @param bool $remember Optional. Remember that the user is logged in
- */
-function wp_setcookie($username, $password = '', $already_md5 = false, $home = '', $siteurl = '', $remember = false) {
-	_deprecated_function( __FUNCTION__, '2.5.0', 'wp_set_auth_cookie()' );
-	$user = get_user_by('login', $username);
-	wp_set_auth_cookie($user->ID, $remember);
-}
+if ( ! function_exists('wp_setcookie') ) :
+	/**
+	 * Sets a cookie for a user who just logged in. This function is deprecated.
+	 *
+	 * @since 1.5.0
+	 * @deprecated 2.5.0 Use wp_set_auth_cookie()
+	 * @see wp_set_auth_cookie()
+	 *
+	 * @param string $username The user's username
+	 * @param string $password Optional. The user's password
+	 * @param bool $already_md5 Optional. Whether the password has already been through MD5
+	 * @param string $home Optional. Will be used instead of COOKIEPATH if set
+	 * @param string $siteurl Optional. Will be used instead of SITECOOKIEPATH if set
+	 * @param bool $remember Optional. Remember that the user is logged in
+	 */
+	function wp_setcookie($username, $password = '', $already_md5 = false, $home = '', $siteurl = '', $remember = false) {
+		_deprecated_function( __FUNCTION__, '2.5.0', 'wp_set_auth_cookie()' );
+		$user = get_user_by('login', $username);
+		wp_set_auth_cookie($user->ID, $remember);
+	}
 else :
 	_deprecated_function( 'wp_setcookie', '2.5.0', 'wp_set_auth_cookie()' );
 endif;
 
-if ( !function_exists('wp_clearcookie') ) :
-/**
- * Clears the authentication cookie, logging the user out. This function is deprecated.
- *
- * @since 1.5.0
- * @deprecated 2.5.0 Use wp_clear_auth_cookie()
- * @see wp_clear_auth_cookie()
- */
-function wp_clearcookie() {
-	_deprecated_function( __FUNCTION__, '2.5.0', 'wp_clear_auth_cookie()' );
-	wp_clear_auth_cookie();
-}
+if ( ! function_exists('wp_clearcookie') ) :
+	/**
+	 * Clears the authentication cookie, logging the user out. This function is deprecated.
+	 *
+	 * @since 1.5.0
+	 * @deprecated 2.5.0 Use wp_clear_auth_cookie()
+	 * @see wp_clear_auth_cookie()
+	 */
+	function wp_clearcookie() {
+		_deprecated_function( __FUNCTION__, '2.5.0', 'wp_clear_auth_cookie()' );
+		wp_clear_auth_cookie();
+	}
 else :
 	_deprecated_function( 'wp_clearcookie', '2.5.0', 'wp_clear_auth_cookie()' );
 endif;
 
-if ( !function_exists('wp_get_cookie_login') ):
-/**
- * Gets the user cookie login. This function is deprecated.
- *
- * This function is deprecated and should no longer be extended as it won't be
- * used anywhere in WordPress. Also, plugins shouldn't use it either.
- *
- * @since 2.0.3
- * @deprecated 2.5.0
- *
- * @return bool Always returns false
- */
-function wp_get_cookie_login() {
-	_deprecated_function( __FUNCTION__, '2.5.0' );
-	return false;
-}
+if ( ! function_exists('wp_get_cookie_login') ):
+	/**
+	 * Gets the user cookie login. This function is deprecated.
+	 *
+	 * This function is deprecated and should no longer be extended as it won't be
+	 * used anywhere in WordPress. Also, plugins shouldn't use it either.
+	 *
+	 * @since 2.0.3
+	 * @deprecated 2.5.0
+	 *
+	 * @return bool Always returns false
+	 */
+	function wp_get_cookie_login() {
+		_deprecated_function( __FUNCTION__, '2.5.0' );
+		return false;
+	}
 else :
 	_deprecated_function( 'wp_get_cookie_login', '2.5.0' );
 endif;
 
-if ( !function_exists('wp_login') ) :
-/**
- * Checks a users login information and logs them in if it checks out. This function is deprecated.
- *
- * Use the global $error to get the reason why the login failed. If the username
- * is blank, no error will be set, so assume blank username on that case.
- *
- * Plugins extending this function should also provide the global $error and set
- * what the error is, so that those checking the global for why there was a
- * failure can utilize it later.
- *
- * @since 1.2.2
- * @deprecated 2.5.0 Use wp_signon()
- * @see wp_signon()
- *
- * @global string $error Error when false is returned
- *
- * @param string $username   User's username
- * @param string $password   User's password
- * @param string $deprecated Not used
- * @return bool True on successful check, false on login failure.
- */
-function wp_login($username, $password, $deprecated = '') {
-	_deprecated_function( __FUNCTION__, '2.5.0', 'wp_signon()' );
-	global $error;
+if ( ! function_exists('wp_login') ) :
+	/**
+	 * Checks a users login information and logs them in if it checks out. This function is deprecated.
+	 *
+	 * Use the global $error to get the reason why the login failed. If the username
+	 * is blank, no error will be set, so assume blank username on that case.
+	 *
+	 * Plugins extending this function should also provide the global $error and set
+	 * what the error is, so that those checking the global for why there was a
+	 * failure can utilize it later.
+	 *
+	 * @since 1.2.2
+	 * @deprecated 2.5.0 Use wp_signon()
+	 * @see wp_signon()
+	 *
+	 * @global string $error Error when false is returned
+	 *
+	 * @param string $username   User's username
+	 * @param string $password   User's password
+	 * @param string $deprecated Not used
+	 * @return bool True on successful check, false on login failure.
+	 */
+	function wp_login($username, $password, $deprecated = '') {
+		_deprecated_function( __FUNCTION__, '2.5.0', 'wp_signon()' );
+		global $error;
 
-	$user = wp_authenticate($username, $password);
+		$user = wp_authenticate($username, $password);
 
-	if ( ! is_wp_error($user) )
-		return true;
+		if ( ! is_wp_error($user) )
+			return true;
 
-	$error = $user->get_error_message();
-	return false;
-}
+		$error = $user->get_error_message();
+		return false;
+	}
 else :
 	_deprecated_function( 'wp_login', '2.5.0', 'wp_signon()' );
 endif;
diff --git src/wp-includes/pomo/plural-forms.php src/wp-includes/pomo/plural-forms.php
index a604334e88..20b9ca36fc 100644
--- src/wp-includes/pomo/plural-forms.php
+++ src/wp-includes/pomo/plural-forms.php
@@ -3,8 +3,11 @@
 /**
  * A gettext Plural-Forms parser.
  *
+ * @package pomo
+ * @subpackage Plural Forms
  * @since 4.9.0
  */
+
 if ( ! class_exists( 'Plural_Forms', false ) ) :
 	#[AllowDynamicProperties]
 	class Plural_Forms {
diff --git src/wp-includes/shortcodes.php src/wp-includes/shortcodes.php
index bddf63ada2..c2912cb83a 100644
--- src/wp-includes/shortcodes.php
+++ src/wp-includes/shortcodes.php
@@ -39,7 +39,10 @@
  * @var array
  * @global array $shortcode_tags
  */
-$shortcode_tags = array();
+if ( ! isset( $shortcode_tags ) ) {
+	$shortcode_tags = array(); // Initialize the global variable if not already set
+}
+
 
 /**
  * Adds a new shortcode.
diff --git src/wp-includes/template-loader.php src/wp-includes/template-loader.php
index 0fd08545cc..a28748a1a9 100644
--- src/wp-includes/template-loader.php
+++ src/wp-includes/template-loader.php
@@ -4,6 +4,7 @@
  *
  * @package WordPress
  */
+
 if ( wp_using_themes() ) {
 	/**
 	 * Fires before determining which template to load.
diff --git src/wp-includes/theme-templates.php src/wp-includes/theme-templates.php
index 55b9c8fac4..e0260443cc 100644
--- src/wp-includes/theme-templates.php
+++ src/wp-includes/theme-templates.php
@@ -1,5 +1,4 @@
 <?php
-
 /**
  * Sets a custom slug when creating auto-draft template parts.
  *