wp_get_installed_translations

 * Since the role names are in the database and not in the source there
 * are dummy gettext calls to get them into the POT file and this function
 * properly translates them back.
 *
 * The before_last_bar() call is needed, because older installations keep the roles
 * using the old context format: 'Role name|User role' and just skipping the
 * content after the last bar is easier than fixing them in the DB. New installations
 * won't suffer from that problem.
 *
 * @since 2.8.0
 * @since 5.2.0 Added the `$domain` parameter.
 *
 * @param string $name   The role name.
 * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
 *                       Default 'default'.
 * @return string Translated role name on success, original name on failure.
 */
function translate_user_role( $name, $domain = 'default' ) {
	return translate_with_gettext_context( before_last_bar( $name ), 'User role', $domain );
}

/**
 * Get all available languages based on the presence of *.mo files in a given directory.
 *
 * The default directory is WP_LANG_DIR.
 *
 * @since 3.0.0
 * @since 4.7.0 The results are now filterable with the {@see 'get_available_languages'} filter.
 *
 * @param string $dir A directory to search for language files.
 *                    Default WP_LANG_DIR.
 * @return string[] An array of language codes or an empty array if no languages are present. Language codes are formed by stripping the .mo extension from the language file names.
 */
function get_available_languages( $dir = null ) {
	$languages = array();

	$lang_files = glob( ( is_null( $dir ) ? WP_LANG_DIR : $dir ) . '/*.mo' );
	if ( $lang_files ) {
		foreach ( $lang_files as $lang_file ) {
			$lang_file = basename( $lang_file, '.mo' );
			if ( 0 !== strpos( $lang_file, 'continents-cities' ) && 0 !== strpos( $lang_file, 'ms-' ) &&
				0 !== strpos( $lang_file, 'admin-' ) ) {
				$languages[] = $lang_file;
			}