'Whether theme opts in to wide alignment CSS class.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'automatic-feed-links',
		array(
			'description'  => __( 'Whether posts and comments RSS feed links are added to head.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'block-templates',
		array(
			'description'  => __( 'Whether a theme uses block-based templates.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'block-template-parts',
		array(
			'description'  => __( 'Whether a theme uses block-based template parts.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'custom-background',
		array(
			'description'  => __( 'Custom background if defined by the theme.' ),
			'type'         => 'object',
			'show_in_rest' => array(
				'schema' => array(
					'properties' => array(
						'default-image'      => array(
							'type'   => 'string',
							'format' => 'uri',
						),
						'default-preset'     => array(
							'type' => 'string',
							'enum' => array(
								'default',
								'fill',
								'fit',
								'repeat',
								'custom',
							),
						),
						'default-position-x' => array(
							'type' => 'string',
							'enum' => array(
								'left',
								'center',
								'right',
							),
						),
						'default-position-y' => array(
							'type' => 'string',
							'enum' => array(
								'left',
								'center',
								'right',
							),
						),
						'default-size'       => array(
							'type' => 'string',
							'enum' => array(
								'auto',
								'contain',
								'cover',
							),
						),
						'default-repeat'     => array(
							'type' => 'string',
							'enum' => array(
								'repeat-x',
								'repeat-y',
								'repeat',
								'no-repeat',
							),
						),
						'default-attachment' => array(
							'type' => 'string',
							'enum' => array(
								'scroll',
								'fixed',
							),
						),
						'default-color'      => array(
							'type' => 'string',
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'custom-header',
		array(
			'description'  => __( 'Custom header if defined by the theme.' ),
			'type'         => 'object',
			'show_in_rest' => array(
				'schema' => array(
					'properties' => array(
						'default-image'      => array(
							'type'   => 'string',
							'format' => 'uri',
						),
						'random-default'     => array(
							'type' => 'boolean',
						),
						'width'              => array(
							'type' => 'integer',
						),
						'height'             => array(
							'type' => 'integer',
						),
						'flex-height'        => array(
							'type' => 'boolean',
						),
						'flex-width'         => array(
							'type' => 'boolean',
						),
						'default-text-color' => array(
							'type' => 'string',
						),
						'header-text'        => array(
							'type' => 'boolean',
						),
						'uploads'            => array(
							'type' => 'boolean',
						),
						'video'              => array(
							'type' => 'boolean',
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'custom-logo',
		array(
			'type'         => 'object',
			'description'  => __( 'Custom logo if defined by the theme.' ),
			'show_in_rest' => array(
				'schema' => array(
					'properties' => array(
						'width'                => array(
							'type' => 'integer',
						),
						'height'               => array(
							'type' => 'integer',
						),
						'flex-width'           => array(
							'type' => 'boolean',
						),
						'flex-height'          => array(
							'type' => 'boolean',
						),
						'header-text'          => array(
							'type'  => 'array',
							'items' => array(
								'type' => 'string',
							),
						),
						'unlink-homepage-logo' => array(
							'type' => 'boolean',
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'customize-selective-refresh-widgets',
		array(
			'description'  => __( 'Whether the theme enables Selective Refresh for Widgets being managed with the Customizer.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'dark-editor-style',
		array(
			'description'  => __( 'Whether theme opts in to the dark editor style UI.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'disable-custom-colors',
		array(
			'description'  => __( 'Whether the theme disables custom colors.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'disable-custom-font-sizes',
		array(
			'description'  => __( 'Whether the theme disables custom font sizes.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'disable-custom-gradients',
		array(
			'description'  => __( 'Whether the theme disables custom gradients.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'disable-layout-styles',
		array(
			'description'  => __( 'Whether the theme disables generated layout styles.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'editor-color-palette',
		array(
			'type'         => 'array',
			'description'  => __( 'Custom color palette if defined by the theme.' ),
			'show_in_rest' => array(
				'schema' => array(
					'items' => array(
						'type'       => 'object',
						'properties' => array(
							'name'  => array(
								'type' => 'string',
							),
							'slug'  => array(
								'type' => 'string',
							),
							'color' => array(
								'type' => 'string',
							),
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'editor-font-sizes',
		array(
			'type'         => 'array',
			'description'  => __( 'Custom font sizes if defined by the theme.' ),
			'show_in_rest' => array(
				'schema' => array(
					'items' => array(
						'type'       => 'object',
						'properties' => array(
							'name' => array(
								'type' => 'string',
							),
							'size' => array(
								'type' => 'number',
							),
							'slug' => array(
								'type' => 'string',
							),
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'editor-gradient-presets',
		array(
			'type'         => 'array',
			'description'  => __( 'Custom gradient presets if defined by the theme.' ),
			'show_in_rest' => array(
				'schema' => array(
					'items' => array(
						'type'       => 'object',
						'properties' => array(
							'name'     => array(
								'type' => 'string',
							),
							'gradient' => array(
								'type' => 'string',
							),
							'slug'     => array(
								'type' => 'string',
							),
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'editor-spacing-sizes',
		array(
			'type'         => 'array',
			'description'  => __( 'Custom spacing sizes if defined by the theme.' ),
			'show_in_rest' => array(
				'schema' => array(
					'items' => array(
						'type'       => 'object',
						'properties' => array(
							'name' => array(
								'type' => 'string',
							),
							'size' => array(
								'type' => 'string',
							),
							'slug' => array(
								'type' => 'string',
							),
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'editor-styles',
		array(
			'description'  => __( 'Whether theme opts in to the editor styles CSS wrapper.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'html5',
		array(
			'type'         => 'array',
			'description'  => __( 'Allows use of HTML5 markup for search forms, comment forms, comment lists, gallery, and caption.' ),
			'show_in_rest' => array(
				'schema' => array(
					'items' => array(
						'type' => 'string',
						'enum' => array(
							'search-form',
							'comment-form',
							'comment-list',
							'gallery',
							'caption',
							'script',
							'style',
						),
					),
				),
			),
		)
	);
	register_theme_feature(
		'post-formats',
		array(
			'type'         => 'array',
			'description'  => __( 'Post formats supported.' ),
			'show_in_rest' => array(
				'name'             => 'formats',
				'schema'           => array(
					'items'   => array(
						'type' => 'string',
						'enum' => get_post_format_slugs(),
					),
					'default' => array( 'standard' ),
				),
				'prepare_callback' => static function ( $formats ) {
					$formats = is_array( $formats ) ? array_values( $formats[0] ) : array();
					$formats = array_merge( array( 'standard' ), $formats );

					return $formats;
				},
			),
		)
	);
	register_theme_feature(
		'post-thumbnails',
		array(
			'type'         => 'array',
			'description'  => __( 'The post types that support thumbnails or true if all post types are supported.' ),
			'show_in_rest' => array(
				'type'   => array( 'boolean', 'array' ),
				'schema' => array(
					'items' => array(
						'type' => 'string',
					),
				),
			),
		)
	);
	register_theme_feature(
		'responsive-embeds',
		array(
			'description'  => __( 'Whether the theme supports responsive embedded content.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'title-tag',
		array(
			'description'  => __( 'Whether the theme can manage the document title tag.' ),
			'show_in_rest' => true,
		)
	);
	register_theme_feature(
		'wp-block-styles',
		array(
			'description'  => __( 'Whether theme opts in to default WordPress block styles for viewing.' ),
			'show_in_rest' => true,
		)
	);
}

/**
 * Returns whether the active theme is a block-based theme or not.
 *
 * @since 5.9.0
 *
 * @return bool Whether the active theme is a block-based theme or not.
 */
function wp_is_block_theme() {
	return wp_get_theme()->is_block_theme();
}

/**
 * Given an element name, returns a class name.
 *
 * Alias of WP_Theme_JSON::get_element_class_name.
 *
 * @since 6.1.0
 *
 * @param string $element The name of the element.
 *
 * @return string The name of the class.
 */
function wp_theme_get_element_class_name( $element ) {
	return WP_Theme_JSON::get_element_class_name( $element );
}

/**
 * Adds default theme supports for block themes when the 'after_setup_theme' action fires.
 *
 * See {@see 'after_setup_theme'}.
 *
 * @since 5.9.0
 * @access private
 */
function _add_default_theme_supports() {
	if ( ! wp_is_block_theme() ) {
		return;
	}

	add_theme_support( 'post-thumbnails' );
	add_theme_support( 'responsive-embeds' );
	add_theme_support( 'editor-styles' );
	/*
	 * Makes block themes support HTML5 by default for the comment block and search form
	 * (which use default template functions) and `[caption]` and `[gallery]` shortcodes.
	 * Other blocks contain their own HTML5 markup.
	 */
	add_theme_support( 'html5', array( 'comment-form', 'comment-list', 'search-form', 'gallery', 'caption', 'style', 'script' ) );
	add_theme_support( 'automatic-feed-links' );

	add_filter( 'should_load_separate_core_block_assets', '__return_true' );

	/*
	 * Remove the Customizer's Menus panel when block theme is active.
	 */
	add_filter(
		'customize_panel_active',
		static function ( $active, WP_Customize_Panel $panel ) {
			if (
				'nav_menus' === $panel->id &&
				! current_theme_supports( 'menus' ) &&
				! current_theme_supports( 'widgets' )
			) {
				$active = false;
			}
			return $active;
		},
		10,
		2
	);
}
<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function add_theme_support() in /home/ocb/public_html/wp-includes/block-patterns.php:9
Stack trace:
#0 /home/ocb/public_html/wp-settings.php(370): require()
#1 /home/ocb/public_html/wp-config.php(77): require_once('/home/ocb/publi...')
#2 /home/ocb/public_html/wp-load.php(50): require_once('/home/ocb/publi...')
#3 /home/ocb/public_html/wp-blog-header.php(13): require_once('/home/ocb/publi...')
#4 /home/ocb/public_html/index.php(17): require('/home/ocb/publi...')
#5 {main}
  thrown in <b>/home/ocb/public_html/wp-includes/block-patterns.php</b> on line <b>9</b><br />
<br />
<b>Fatal error</b>:  Uncaught Error: Call to a member function set() on null in /home/ocb/public_html/wp-includes/l10n.php:856
Stack trace:
#0 /home/ocb/public_html/wp-includes/l10n.php(959): load_textdomain('default', '/home/ocb/publi...', 'lv')
#1 /home/ocb/public_html/wp-includes/class-wp-fatal-error-handler.php(49): load_default_textdomain()
#2 [internal function]: WP_Fatal_Error_Handler-&gt;handle()
#3 {main}
  thrown in <b>/home/ocb/public_html/wp-includes/l10n.php</b> on line <b>856</b><br />