diff --git a/wp-admin/edit-tags.php b/wp-admin/edit-tags.php
index b575a838d9..dbd630af56 100644
--- a/wp-admin/edit-tags.php
+++ b/wp-admin/edit-tags.php
@@ -544,7 +544,7 @@ do_action( "{$taxonomy}_add_form", $taxonomy );
 		/* translators: %s: default category */
 		__( 'Deleting a category does not delete the posts in that category. Instead, posts that were only assigned to the deleted category are set to the category %s.' ),
 		/** This filter is documented in wp-includes/category-template.php */
-		'<strong>' . apply_filters( 'the_category', get_cat_name( get_option( 'default_category') ) ) . '</strong>'
+		'<strong>' . apply_filters( 'the_category', get_cat_name( get_option( 'default_category') ), '', '' ) . '</strong>'
 	);
 	?>
 </p>
diff --git a/wp-admin/includes/class-walker-category-checklist.php b/wp-admin/includes/class-walker-category-checklist.php
index 966244eb78..3ed2a493dd 100644
--- a/wp-admin/includes/class-walker-category-checklist.php
+++ b/wp-admin/includes/class-walker-category-checklist.php
@@ -96,14 +96,14 @@ class Walker_Category_Checklist extends Walker {
 			$output .= "\n" . '<li' . $class . '>' .
 				'<div class="' . $inner_class . '" data-term-id=' . $category->term_id .
 				' tabindex="0" role="checkbox" aria-checked="' . $aria_checked . '">' .
-				esc_html( apply_filters( 'the_category', $category->name ) ) . '</div>';
+				esc_html( apply_filters( 'the_category', $category->name, '', '' ) ) . '</div>';
 		} else {
 			/** This filter is documented in wp-includes/category-template.php */
 			$output .= "\n<li id='{$taxonomy}-{$category->term_id}'$class>" .
 				'<label class="selectit"><input value="' . $category->term_id . '" type="checkbox" name="'.$name.'[]" id="in-'.$taxonomy.'-' . $category->term_id . '"' .
 				checked( in_array( $category->term_id, $args['selected_cats'] ), true, false ) .
 				disabled( empty( $args['disabled'] ), false, false ) . ' /> ' .
-				esc_html( apply_filters( 'the_category', $category->name ) ) . '</label>';
+				esc_html( apply_filters( 'the_category', $category->name, '', '' ) ) . '</label>';
 		}
 	}
 
diff --git a/wp-admin/includes/template.php b/wp-admin/includes/template.php
index 8385c90670..4846fcd906 100644
--- a/wp-admin/includes/template.php
+++ b/wp-admin/includes/template.php
@@ -214,7 +214,7 @@ function wp_popular_terms_checklist( $taxonomy, $default = 0, $number = 10, $ech
 				<input id="in-<?php echo $id; ?>" type="checkbox" <?php echo $checked; ?> value="<?php echo (int) $term->term_id; ?>" <?php disabled( ! current_user_can( $tax->cap->assign_terms ) ); ?> />
 				<?php
 				/** This filter is documented in wp-includes/category-template.php */
-				echo esc_html( apply_filters( 'the_category', $term->name ) );
+				echo esc_html( apply_filters( 'the_category', $term->name, '', '' ) );
 				?>
 			</label>
 		</li>
@@ -255,7 +255,7 @@ function wp_link_category_checklist( $link_id = 0 ) {
 		$cat_id = $category->term_id;
 
 		/** This filter is documented in wp-includes/category-template.php */
-		$name = esc_html( apply_filters( 'the_category', $category->name ) );
+		$name = esc_html( apply_filters( 'the_category', $category->name, '', '' ) );
 		$checked = in_array( $cat_id, $checked_categories ) ? ' checked="checked"' : '';
 		echo '<li id="link-category-', $cat_id, '"><label for="in-link-category-', $cat_id, '" class="selectit"><input value="', $cat_id, '" type="checkbox" name="link_category[]" id="in-link-category-', $cat_id, '"', $checked, '/> ', $name, "</label></li>";
 	}
diff --git a/wp-includes/category-template.php b/wp-includes/category-template.php
index 5a36067533..c9bf0d2f73 100644
--- a/wp-includes/category-template.php
+++ b/wp-includes/category-template.php
@@ -386,9 +386,10 @@ function wp_dropdown_categories( $args = '' ) {
 		 *
 		 * @see wp_dropdown_categories()
 		 *
-		 * @param string $element Taxonomy element to list.
+		 * @param string       $element  Category name.
+		 * @param WP_Term|null $category The category object, or null if there's no corresponding category.
 		 */
-		$show_option_none = apply_filters( 'list_cats', $r['show_option_none'] );
+		$show_option_none = apply_filters( 'list_cats', $r['show_option_none'], null );
 		$output .= "\t<option value='" . esc_attr( $option_none_value ) . "' selected='selected'>$show_option_none</option>\n";
 	}
 
@@ -397,7 +398,7 @@ function wp_dropdown_categories( $args = '' ) {
 		if ( $r['show_option_all'] ) {
 
 			/** This filter is documented in wp-includes/category-template.php */
-			$show_option_all = apply_filters( 'list_cats', $r['show_option_all'] );
+			$show_option_all = apply_filters( 'list_cats', $r['show_option_all'], null );
 			$selected = ( '0' === strval($r['selected']) ) ? " selected='selected'" : '';
 			$output .= "\t<option value='0'$selected>$show_option_all</option>\n";
 		}
@@ -405,7 +406,7 @@ function wp_dropdown_categories( $args = '' ) {
 		if ( $r['show_option_none'] ) {
 
 			/** This filter is documented in wp-includes/category-template.php */
-			$show_option_none = apply_filters( 'list_cats', $r['show_option_none'] );
+			$show_option_none = apply_filters( 'list_cats', $r['show_option_none'], null );
 			$selected = selected( $option_none_value, $r['selected'], false );
 			$output .= "\t<option value='" . esc_attr( $option_none_value ) . "'$selected>$show_option_none</option>\n";
 		}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d0a6c033c5..0ce1566a84 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-41220';
+$wp_version = '4.9-alpha-41221';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.