Source

File: wp-includes/class-wp.php

if ( is_author() && is_numeric( $author ) && $author > 0 && is_user_member_of_blog( $author )
				// Don't 404 for these queries if they matched an object.
				|| ( is_tag() || is_category() || is_tax() || is_post_type_archive() ) && get_queried_object()