diff --git a/src/Plugin_Command.php b/src/Plugin_Command.php
index 9a82fcccc..5ce246aca 100644
--- a/src/Plugin_Command.php
+++ b/src/Plugin_Command.php
@@ -1216,6 +1216,10 @@ private function get_plugin_dependencies( $slug ) {
 			return [];
 		}
 
+		/**
+		 * @var object{requires_plugins?: array} $api
+		 */
+
 		// Check if requires_plugins field exists and is not empty
 		if ( ! empty( $api->requires_plugins ) && is_array( $api->requires_plugins ) ) {
 			return $api->requires_plugins;
diff --git a/src/WP_CLI/CommandWithUpgrade.php b/src/WP_CLI/CommandWithUpgrade.php
index 63c7776e9..8326c168d 100755
--- a/src/WP_CLI/CommandWithUpgrade.php
+++ b/src/WP_CLI/CommandWithUpgrade.php
@@ -81,6 +81,9 @@ abstract protected function get_item_list();
 	 */
 	abstract protected function filter_item_list( $items, $args );
 
+	/**
+	 * @return array<string, array{slug: string, name: string, update: string, recently_active?: bool, status: string, version: string}>
+	 */
 	abstract protected function get_all_items();
 
 	/**
@@ -237,6 +240,11 @@ public function install( $args, $assoc_args ) {
 						&& ! preg_match( '#github\.com/[^/]+/[^/]+/(?:releases/download|raw)/#', $slug ) ) {
 
 					$filter = function ( $source ) use ( $slug ) {
+						/**
+						 * @var \WP_Filesystem_Base $wp_filesystem
+						 */
+						global $wp_filesystem;
+
 						/**
 						 * @var string $path
 						 */
@@ -255,7 +263,7 @@ public function install( $args, $assoc_args ) {
 						}
 						$new_path = substr_replace( $source, $slug_dir, (int) strrpos( $source, $source_dir ), strlen( $source_dir ) );
 
-						if ( $GLOBALS['wp_filesystem']->move( $source, $new_path ) ) {
+						if ( $wp_filesystem->move( $source, $new_path ) ) {
 							WP_CLI::log( sprintf( "Renamed Github-based project from '%s' to '%s'.", $source_dir, $slug_dir ) );
 							return $new_path;
 						}
@@ -874,6 +882,9 @@ protected function _search( $args, $assoc_args ) {
 		// In older WP versions these used to be objects.
 		foreach ( $items as $index => $item_object ) {
 			if ( is_array( $item_object ) ) {
+				/**
+				 * @var array{slug: string} $item_object
+				 */
 				$items[ $index ]['url'] = "https://wordpress.org/{$plural}/{$item_object['slug']}/";
 			} elseif ( $item_object instanceof \stdClass ) {
 				$item_object->url = "https://wordpress.org/{$plural}/{$item_object->slug}/";
diff --git a/src/WP_CLI/ExtensionUpgraderSkin.php b/src/WP_CLI/ExtensionUpgraderSkin.php
index 3c9db76ea..cef43ad27 100644
--- a/src/WP_CLI/ExtensionUpgraderSkin.php
+++ b/src/WP_CLI/ExtensionUpgraderSkin.php
@@ -8,6 +8,9 @@
  * An Upgrader Skin for extensions (plugins/themes) that displays which item is being updated
  *
  * @package wp-cli
+ *
+ * @property-read array{Name?: string}|null $plugin_info
+ * @property-read \WP_Theme|null $theme_info
  */
 class ExtensionUpgraderSkin extends UpgraderSkin {
 
@@ -15,6 +18,7 @@ class ExtensionUpgraderSkin extends UpgraderSkin {
 	 * Called before an update is performed.
 	 */
 	public function before() {
+		// These properties are defined in `Bulk_Plugin_Upgrader_Skin`/`Bulk_Theme_Upgrader_Skin`
 		if ( isset( $this->plugin_info ) && is_array( $this->plugin_info ) && isset( $this->plugin_info['Name'] ) ) {
 			WP_CLI::log( sprintf( 'Updating %s...', html_entity_decode( $this->plugin_info['Name'], ENT_QUOTES, get_bloginfo( 'charset' ) ) ) );
 		} elseif ( isset( $this->theme_info ) && is_object( $this->theme_info ) && method_exists( $this->theme_info, 'get' ) ) {
diff --git a/src/WP_CLI/ParseThemeNameInput.php b/src/WP_CLI/ParseThemeNameInput.php
index 5a4def568..2c177f2fd 100644
--- a/src/WP_CLI/ParseThemeNameInput.php
+++ b/src/WP_CLI/ParseThemeNameInput.php
@@ -58,7 +58,7 @@ private function get_all_themes() {
 
 		if ( is_multisite() ) {
 			/**
-			 * @var array<string, array{enabled: string}>} $site_enabled
+			 * @var array<string, array{enabled: string}> $site_enabled
 			 */
 			$site_enabled = get_option( 'allowedthemes' );
 			if ( empty( $site_enabled ) ) {
@@ -66,7 +66,7 @@ private function get_all_themes() {
 			}
 
 			/**
-			 * @var array<string, array{enabled: string}>} $network_enabled
+			 * @var array<string, array{enabled: string}> $network_enabled
 			 */
 			$network_enabled = get_site_option( 'allowedthemes' );
 			if ( empty( $network_enabled ) ) {