_add_default_theme_supports() WordPress Function

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' );
}