Source

File: wp-includes/sitemaps/providers/class-wp-sitemaps-users.php

protected function get_users_query_args() {
		$public_post_types = get_post_types(
			array(
				'public' => true,
			)
		);

		// We're not supporting sitemaps for author pages for attachments.
		unset( $public_post_types['attachment'] );

		/**
		 * Filters the query arguments for authors with public posts.
		 *
		 * Allows modification of the authors query arguments before querying.
		 *
		 * @see WP_User_Query for a full list of arguments
		 *
		 * @since 5.5.0
		 *
		 * @param array $args Array of WP_User_Query arguments.
		 */
		$args = apply_filters(
			'wp_sitemaps_users_query_args',
			array(
				'has_published_posts' => array_keys( $public_post_types ),
				'number'              => wp_sitemaps_get_max_urls( $this->object_type ),
			)
		);

		return $args;
	}