WordPress at a glance
function is not described

register_initial_settings() WP 4.7.0

Register default settings available in WordPress.

The settings registered here are primarily useful for the REST API, so this does not encompass all settings available in WordPress.

No Hooks.

Return

Nothing (null).

Usage

register_initial_settings();

Code of register initial settings: wp-includes/option.php VER 5.1.1

<?php
function register_initial_settings() {
	register_setting(
		'general',
		'blogname',
		array(
			'show_in_rest' => array(
				'name' => 'title',
			),
			'type'         => 'string',
			'description'  => __( 'Site title.' ),
		)
	);

	register_setting(
		'general',
		'blogdescription',
		array(
			'show_in_rest' => array(
				'name' => 'description',
			),
			'type'         => 'string',
			'description'  => __( 'Site tagline.' ),
		)
	);

	if ( ! is_multisite() ) {
		register_setting(
			'general',
			'siteurl',
			array(
				'show_in_rest' => array(
					'name'   => 'url',
					'schema' => array(
						'format' => 'uri',
					),
				),
				'type'         => 'string',
				'description'  => __( 'Site URL.' ),
			)
		);
	}

	if ( ! is_multisite() ) {
		register_setting(
			'general',
			'admin_email',
			array(
				'show_in_rest' => array(
					'name'   => 'email',
					'schema' => array(
						'format' => 'email',
					),
				),
				'type'         => 'string',
				'description'  => __( 'This address is used for admin purposes, like new user notification.' ),
			)
		);
	}

	register_setting(
		'general',
		'timezone_string',
		array(
			'show_in_rest' => array(
				'name' => 'timezone',
			),
			'type'         => 'string',
			'description'  => __( 'A city in the same timezone as you.' ),
		)
	);

	register_setting(
		'general',
		'date_format',
		array(
			'show_in_rest' => true,
			'type'         => 'string',
			'description'  => __( 'A date format for all date strings.' ),
		)
	);

	register_setting(
		'general',
		'time_format',
		array(
			'show_in_rest' => true,
			'type'         => 'string',
			'description'  => __( 'A time format for all time strings.' ),
		)
	);

	register_setting(
		'general',
		'start_of_week',
		array(
			'show_in_rest' => true,
			'type'         => 'integer',
			'description'  => __( 'A day number of the week that the week should start on.' ),
		)
	);

	register_setting(
		'general',
		'WPLANG',
		array(
			'show_in_rest' => array(
				'name' => 'language',
			),
			'type'         => 'string',
			'description'  => __( 'WordPress locale code.' ),
			'default'      => 'en_US',
		)
	);

	register_setting(
		'writing',
		'use_smilies',
		array(
			'show_in_rest' => true,
			'type'         => 'boolean',
			'description'  => __( 'Convert emoticons like :-) and :-P to graphics on display.' ),
			'default'      => true,
		)
	);

	register_setting(
		'writing',
		'default_category',
		array(
			'show_in_rest' => true,
			'type'         => 'integer',
			'description'  => __( 'Default post category.' ),
		)
	);

	register_setting(
		'writing',
		'default_post_format',
		array(
			'show_in_rest' => true,
			'type'         => 'string',
			'description'  => __( 'Default post format.' ),
		)
	);

	register_setting(
		'reading',
		'posts_per_page',
		array(
			'show_in_rest' => true,
			'type'         => 'integer',
			'description'  => __( 'Blog pages show at most.' ),
			'default'      => 10,
		)
	);

	register_setting(
		'discussion',
		'default_ping_status',
		array(
			'show_in_rest' => array(
				'schema' => array(
					'enum' => array( 'open', 'closed' ),
				),
			),
			'type'         => 'string',
			'description'  => __( 'Allow link notifications from other blogs (pingbacks and trackbacks) on new articles.' ),
		)
	);

	register_setting(
		'discussion',
		'default_comment_status',
		array(
			'show_in_rest' => array(
				'schema' => array(
					'enum' => array( 'open', 'closed' ),
				),
			),
			'type'         => 'string',
			'description'  => __( 'Allow people to post comments on new articles.' ),
		)
	);
}