Index: wp-includes/option.php
===================================================================
--- wp-includes/option.php	(revision 39258)
+++ wp-includes/option.php	(working copy)
@@ -1734,7 +1734,7 @@
 			'name' => 'description',
 		),
 		'type'         => 'string',
-		'description'  => __( 'Site description.' ),
+		'description'  => __( 'Site tagline.' ),
 	) );
 
 	register_setting( 'general', 'siteurl', array(
@@ -1804,7 +1804,7 @@
 	register_setting( 'writing', 'default_category', array(
 		'show_in_rest' => true,
 		'type'         => 'integer',
-		'description'  => __( 'Default category.' ),
+		'description'  => __( 'Default post category.' ),
 	) );
 
 	register_setting( 'writing', 'default_post_format', array(