* Retrieves or displays the time from the page start to when function is called.
 *
 * @since 0.71
 *
 * @global float   $timestart Seconds from when timer_start() is called.
 * @global float   $timeend   Seconds from when function is called.
 *
 * @param int|bool $display   Whether to echo or return the results. Accepts 0|false for return,
 *                            1|true for echo. Default 0|false.
 * @param int      $precision The number of digits from the right of the decimal to display.
 *                            Default 3.
 * @return string The "second.microsecond" finished time calculation. The number is formatted
 *                for human consumption, both localized and rounded.
 */
function timer_stop( $display = 0, $precision = 3 ) {
	global $timestart, $timeend;

	$timeend   = microtime( true );
	$timetotal = $timeend - $timestart;

	if ( function_exists( 'number_format_i18n' ) ) {
		$r = number_format_i18n( $timetotal, $precision );
	} else {
		$r = number_format( $timetotal, $precision );
	}

	if ( $display ) {
		echo $r;
	}

	return $r;
}

/**
 * Sets PHP error reporting based on WordPress debug settings.
 *
 * Uses three constants: `WP_DEBUG`, `WP_DEBUG_DISPLAY`, and `WP_DEBUG_LOG`.
 * All three can be defined in wp-config.php. By default, `WP_DEBUG` and
 * `WP_DEBUG_LOG` are set to false, and `WP_DEBUG_DISPLAY` is set to true.
 *
 * When `WP_DEBUG` is true, all PHP notices are reported. WordPress will also
 * display internal notices: when a deprecated WordPress function, function
 * argument, or file is used. Deprecated code may be removed from a later
 * version.
 *
 * It is strongly recommended that plugin and theme developers use `WP_DEBUG`
 * in their development environments.
 *
 * `WP_DEBUG_DISPLAY` and `WP_DEBUG_LOG` perform no function unless `WP_DEBUG`
 * is true.
 *
 * When `WP_DEBUG_DISPLAY` is true, WordPress will force errors to be displayed.
 * `WP_DEBUG_DISPLAY` defaults to true. Defining it as null prevents WordPress
 * from changing the global configuration setting. Defining `WP_DEBUG_DISPLAY`
 * as false will force errors to be hidden.
 *
 * When `WP_DEBUG_LOG` is true, errors will be logged to `wp-content/debug.log`.
 * When `WP_DEBUG_LOG` is a valid path, errors will be logged to the specified file.
 *
 * Errors are never displayed for XML-RPC, REST, `ms-files.php`, and Ajax requests.
 *
 * @since 3.0.0
 * @since 5.1.0 `WP_DEBUG_LOG` can be a file path.
 * @access private
 */
function wp_debug_mode() {
	/**
	 * Filters whether to allow the debug mode check to occur.
	 *
	 * This filter runs before it can be used by plugins. It is designed for
	 * non-web runtimes. Returning false causes the `WP_DEBUG` and related
	 * constants to not be checked and the default PHP values for errors
	 * will be used unless you take care to update them yourself.
	 *
	 * To use this filter you must define a `$wp_filter` global before
	 * WordPress loads, usually in `wp-config.php`.
	 *
	 * Example:
	 *
	 *     $GLOBALS['wp_filter'] = array(
	 *         'enable_wp_debug_mode_checks' => array(
	 *             10 => array(
	 *                 array(
	 *                     'accepted_args' => 0,
	 *                     'function'      => function() {
	 *                         return false;
	 *                     },
	 *                 ),
	 *             ),
	 *         ),
	 *     );
	 *
	 * @since 4.6.0
	 *
	 * @param bool $enable_debug_mode Whether to enable debug mode checks to occur. Default true.
	 */
	if ( ! apply_filters( 'enable_wp_debug_mode_checks', true ) ) {
		return;
	}

	if ( WP_DEBUG ) {
		error_reporting( E_ALL );

		if ( WP_DEBUG_DISPLAY ) {
			ini_set( 'display_errors', 1 );
		} elseif ( null !== WP_DEBUG_DISPLAY ) {
			ini_set( 'display_errors', 0 );
		}

		if ( in_array( strtolower( (string) WP_DEBUG_LOG ), array( 'true', '1' ), true ) ) {
			$log_path = WP_CONTENT_DIR . '/debug.log';
		} elseif ( is_string( WP_DEBUG_LOG ) ) {
			$log_path = WP_DEBUG_LOG;
		} else {
			$log_path = false;
		}

		if ( $log_path ) {
			ini_set( 'log_errors', 1 );
			ini_set( 'error_log', $log_path );
		}
	} else {
		error_reporting( E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR | E_USER_WARNING | E_RECOVERABLE_ERROR );
	}

	/*
	 * The 'REST_REQUEST' check here is optimistic as the constant is most
	 * likely not set at this point even if it is in fact a REST request.
	 */
	if ( defined( 'XMLRPC_REQUEST' ) || defined( 'REST_REQUEST' ) || defined( 'MS_FILES_REQUEST' )
		|| ( defined( 'WP_INSTALLING' ) && WP_INSTALLING )
		|| wp_doing_ajax() || wp_is_json_request()
	) {
		ini_set( 'display_errors', 0 );
	}
}

/**
 * Sets the location of the language directory.
 *
 * To set directory manually, define the `WP_LANG_DIR` constant
 * in wp-config.php.
 *
 * If the language directory exists within `WP_CONTENT_DIR`, it
 * is used. Otherwise the language directory is assumed to live
 * in `WPINC`.
 *
 * @since 3.0.0
 * @access private
 */
function wp_set_lang_dir() {
	if ( ! defined( 'WP_LANG_DIR' ) ) {
		if ( file_exists( WP_CONTENT_DIR . '/languages' ) && @is_dir( WP_CONTENT_DIR . '/languages' )
			|| ! @is_dir( ABSPATH . WPINC . '/languages' )
		) {
			/**
			 * Server path of the language directory.
			 *
			 * No leading slash, no trailing slash, full path, not relative to ABSPATH
			 *