diff --git a/wp-admin/includes/class-wp-comments-list-table.php b/wp-admin/includes/class-wp-comments-list-table.php
index d62020039d..a027e800cd 100644
--- a/wp-admin/includes/class-wp-comments-list-table.php
+++ b/wp-admin/includes/class-wp-comments-list-table.php
@@ -1047,10 +1047,12 @@ class WP_Comments_List_Table extends WP_List_Table {
 	}
 
 	/**
-	 * @param WP_Comment $comment     The comment object.
+	 * @since 5.9.0 Renamed `$comment` to `$item` to match parent class for PHP 8 named param.
+	 *
+	 * @param WP_Comment $item        The comment object.
 	 * @param string     $column_name The custom column's name.
 	 */
-	public function column_default( $comment, $column_name ) {
+	public function column_default( $item, $column_name ) {
 		/**
 		 * Fires when the default column output is displayed for a single row.
 		 *
@@ -1059,6 +1061,6 @@ class WP_Comments_List_Table extends WP_List_Table {
 		 * @param string $column_name The custom column's name.
 		 * @param int    $comment_id  The custom column's unique ID number.
 		 */
-		do_action( 'manage_comments_custom_column', $column_name, $comment->comment_ID );
+		do_action( 'manage_comments_custom_column', $column_name, $item->comment_ID );
 	}
 }
diff --git a/wp-admin/includes/class-wp-links-list-table.php b/wp-admin/includes/class-wp-links-list-table.php
index b867a8ad19..60ba8ed778 100644
--- a/wp-admin/includes/class-wp-links-list-table.php
+++ b/wp-admin/includes/class-wp-links-list-table.php
@@ -279,11 +279,12 @@ class WP_Links_List_Table extends WP_List_Table {
 	 * Handles the default column output.
 	 *
 	 * @since 4.3.0
+	 * @since 5.9.0 Renamed `$link` to `$item` to match parent class for PHP 8 named param.
 	 *
-	 * @param object $link        Link object.
+	 * @param object $item        Link object.
 	 * @param string $column_name Current column name.
 	 */
-	public function column_default( $link, $column_name ) {
+	public function column_default( $item, $column_name ) {
 		/**
 		 * Fires for each registered custom link column.
 		 *
@@ -292,7 +293,7 @@ class WP_Links_List_Table extends WP_List_Table {
 		 * @param string $column_name Name of the custom column.
 		 * @param int    $link_id     Link ID.
 		 */
-		do_action( 'manage_link_custom_column', $column_name, $link->link_id );
+		do_action( 'manage_link_custom_column', $column_name, $item->link_id );
 	}
 
 	public function display_rows() {
diff --git a/wp-admin/includes/class-wp-media-list-table.php b/wp-admin/includes/class-wp-media-list-table.php
index 275d07caca..6c0a499001 100644
--- a/wp-admin/includes/class-wp-media-list-table.php
+++ b/wp-admin/includes/class-wp-media-list-table.php
@@ -594,11 +594,15 @@ class WP_Media_List_Table extends WP_List_Table {
 	 * Handles output for the default column.
 	 *
 	 * @since 4.3.0
+	 * @since 5.9.0 Renamed `$post` to `$item` to match parent class for PHP 8 named param.
 	 *
-	 * @param WP_Post $post        The current WP_Post object.
+	 * @param WP_Post $item        The current WP_Post object.
 	 * @param string  $column_name Current column name.
 	 */
-	public function column_default( $post, $column_name ) {
+	public function column_default( $item, $column_name ) {
+		// Restores the more descriptive, specific name for use within this method.
+		$post = $item;
+
 		if ( 'categories' === $column_name ) {
 			$taxonomy = 'category';
 		} elseif ( 'tags' === $column_name ) {
diff --git a/wp-admin/includes/class-wp-ms-sites-list-table.php b/wp-admin/includes/class-wp-ms-sites-list-table.php
index b928ee92c6..02f7938ead 100644
--- a/wp-admin/includes/class-wp-ms-sites-list-table.php
+++ b/wp-admin/includes/class-wp-ms-sites-list-table.php
@@ -560,11 +560,12 @@ class WP_MS_Sites_List_Table extends WP_List_Table {
 	 * Handles output for the default column.
 	 *
 	 * @since 4.3.0
+	 * @since 5.9.0 Renamed `$blog` to `$item` to match parent class for PHP 8 named param.
 	 *
-	 * @param array  $blog        Current site.
+	 * @param array  $item        Current site.
 	 * @param string $column_name Current column name.
 	 */
-	public function column_default( $blog, $column_name ) {
+	public function column_default( $item, $column_name ) {
 		/**
 		 * Fires for each registered custom column in the Sites list table.
 		 *
@@ -573,7 +574,7 @@ class WP_MS_Sites_List_Table extends WP_List_Table {
 		 * @param string $column_name The name of the column to display.
 		 * @param int    $blog_id     The site ID.
 		 */
-		do_action( 'manage_sites_custom_column', $column_name, $blog['blog_id'] );
+		do_action( 'manage_sites_custom_column', $column_name, $item['blog_id'] );
 	}
 
 	/**
diff --git a/wp-admin/includes/class-wp-ms-themes-list-table.php b/wp-admin/includes/class-wp-ms-themes-list-table.php
index d7d20e238a..d4ad43df57 100644
--- a/wp-admin/includes/class-wp-ms-themes-list-table.php
+++ b/wp-admin/includes/class-wp-ms-themes-list-table.php
@@ -855,13 +855,12 @@ class WP_MS_Themes_List_Table extends WP_List_Table {
 	 * Handles default column output.
 	 *
 	 * @since 4.3.0
+	 * @since 5.9.0 Renamed `$theme` to `$item` to match parent class for PHP 8 named param.
 	 *
-	 * @param WP_Theme $theme       The current WP_Theme object.
+	 * @param WP_Theme $item        The current WP_Theme object.
 	 * @param string   $column_name The current column name.
 	 */
-	public function column_default( $theme, $column_name ) {
-		$stylesheet = $theme->get_stylesheet();
-
+	public function column_default( $item, $column_name ) {
 		/**
 		 * Fires inside each custom column of the Multisite themes list table.
 		 *
@@ -871,7 +870,12 @@ class WP_MS_Themes_List_Table extends WP_List_Table {
 		 * @param string   $stylesheet  Directory name of the theme.
 		 * @param WP_Theme $theme       Current WP_Theme object.
 		 */
-		do_action( 'manage_themes_custom_column', $column_name, $stylesheet, $theme );
+		do_action(
+			'manage_themes_custom_column',
+			$column_name,
+			$item->get_stylesheet(), // Directory name of the theme.
+			$item // Theme object.
+		);
 	}
 
 	/**
diff --git a/wp-admin/includes/class-wp-ms-users-list-table.php b/wp-admin/includes/class-wp-ms-users-list-table.php
index 8e1656ed6c..825f8e86ef 100644
--- a/wp-admin/includes/class-wp-ms-users-list-table.php
+++ b/wp-admin/includes/class-wp-ms-users-list-table.php
@@ -442,13 +442,19 @@ class WP_MS_Users_List_Table extends WP_List_Table {
 	 * Handles the default column output.
 	 *
 	 * @since 4.3.0
+	 * @since 5.9.0 Renamed `$user` to `$item` to match parent class for PHP 8 named param.
 	 *
-	 * @param WP_User $user        The current WP_User object.
+	 * @param WP_User $item        The current WP_User object.
 	 * @param string  $column_name The current column name.
 	 */
-	public function column_default( $user, $column_name ) {
+	public function column_default( $item, $column_name ) {
 		/** This filter is documented in wp-admin/includes/class-wp-users-list-table.php */
-		echo apply_filters( 'manage_users_custom_column', '', $column_name, $user->ID );
+		echo apply_filters(
+			'manage_users_custom_column',
+			'', // Custom column output. Default empty.
+			$column_name,
+			$item->ID // User ID.
+		);
 	}
 
 	public function display_rows() {
diff --git a/wp-admin/includes/class-wp-posts-list-table.php b/wp-admin/includes/class-wp-posts-list-table.php
index f8687efb95..9b3a03b1c0 100644
--- a/wp-admin/includes/class-wp-posts-list-table.php
+++ b/wp-admin/includes/class-wp-posts-list-table.php
@@ -1235,11 +1235,15 @@ class WP_Posts_List_Table extends WP_List_Table {
 	 * Handles the default column output.
 	 *
 	 * @since 4.3.0
+	 * @since 5.9.0 Renamed `$post` to `$item` to match parent class for PHP 8 named param.
 	 *
-	 * @param WP_Post $post        The current WP_Post object.
+	 * @param WP_Post $item        The current WP_Post object.
 	 * @param string  $column_name The current column name.
 	 */
-	public function column_default( $post, $column_name ) {
+	public function column_default( $item, $column_name ) {
+		// Restores the more descriptive, specific name for use within this method.
+		$post = $item;
+
 		if ( 'categories' === $column_name ) {
 			$taxonomy = 'category';
 		} elseif ( 'tags' === $column_name ) {
diff --git a/wp-admin/includes/class-wp-terms-list-table.php b/wp-admin/includes/class-wp-terms-list-table.php
index f6697f13a9..ef4b37ee4d 100644
--- a/wp-admin/includes/class-wp-terms-list-table.php
+++ b/wp-admin/includes/class-wp-terms-list-table.php
@@ -620,11 +620,13 @@ class WP_Terms_List_Table extends WP_List_Table {
 	}
 
 	/**
-	 * @param WP_Term $tag         Term object.
+	 * @since 5.9.0 Renamed `$tag` to `$item` to match parent class for PHP 8 named param.
+	 *
+	 * @param WP_Term $item        Term object.
 	 * @param string  $column_name Name of the column.
 	 * @return string
 	 */
-	public function column_default( $tag, $column_name ) {
+	public function column_default( $item, $column_name ) {
 		/**
 		 * Filters the displayed columns in the terms list table.
 		 *
@@ -638,11 +640,11 @@ class WP_Terms_List_Table extends WP_List_Table {
 		 *
 		 * @since 2.8.0
 		 *
-		 * @param string $string      Blank string.
+		 * @param string $string      Custom column output. Default empty.
 		 * @param string $column_name Name of the column.
 		 * @param int    $term_id     Term ID.
 		 */
-		return apply_filters( "manage_{$this->screen->taxonomy}_custom_column", '', $column_name, $tag->term_id );
+		return apply_filters( "manage_{$this->screen->taxonomy}_custom_column", '', $column_name, $item->term_id );
 	}
 
 	/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0d3c5f83ed..7e5ac18a90 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51727';
+$wp_version = '5.9-alpha-51728';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.