Add the generic strings to WP_Upgrader::$strings.


File: wp-admin/includes/class-wp-upgrader.php

	public function generic_strings() {
		$this->strings['bad_request'] = __('Invalid data provided.');
		$this->strings['fs_unavailable'] = __('Could not access filesystem.');
		$this->strings['fs_error'] = __('Filesystem error.');
		$this->strings['fs_no_root_dir'] = __('Unable to locate ClassicPress root directory.');
		$this->strings['fs_no_content_dir'] = __('Unable to locate ClassicPress content directory (wp-content).');
		$this->strings['fs_no_plugins_dir'] = __('Unable to locate ClassicPress plugin directory.');
		$this->strings['fs_no_themes_dir'] = __('Unable to locate ClassicPress theme directory.');
		/* translators: %s: directory name */
		$this->strings['fs_no_folder'] = __('Unable to locate needed folder (%s).');

		$this->strings['download_failed'] = __('Download failed.');
		$this->strings['installing_package'] = __('Installing the latest version…');
		$this->strings['no_files'] = __('The package contains no files.');
		$this->strings['folder_exists'] = __('Destination folder already exists.');
		$this->strings['mkdir_failed'] = __('Could not create directory.');
		$this->strings['incompatible_archive'] = __('The package could not be installed.');
		$this->strings['files_not_writable'] = __( 'The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.' );

		$this->strings['maintenance_start'] = __('Enabling Maintenance mode…');
		$this->strings['maintenance_end'] = __('Disabling Maintenance mode…');


Version Description
WP-2.8.0 Introduced.