access for editor role

Are you sure?
I checked it now.
As editor I’m trying open this page:
wp-admin/admin.php?page=mlang – polylang page
and I have “Sorry, you are not allowed to access this page.”

Sorry ??. In fact it’s not default in Polylang.
I had overlooked that I once gave editors permission to Polyang in functions.php:

add_action( 'admin_menu', function() {
  if ( ! current_user_can( 'manage_options' ) && function_exists( 'PLL' ) ) {
    add_menu_page( __( 'Strings translations', 'polylang' ), __( 'Languages', 'polylang' ), 'edit_pages', 'mlang_strings', array( PLL(), 'languages_page' ), 'dashicons-translation' );
  }
} );

But still, it would be handy to optionally allow editors (translators) to use TTfP.

ok, You can ovveride access in TTfP too, for example:

add_action('init', 'custom_init');

function custom_init()
{
    if (Polylang_TT_access::get_instance()->is_polylang_page()) {
            $plugin_obj = new Polylang_Theme_Translation();
            $plugin_obj->run();
    }
}

Works. Thank you!

great, please rate my plugin if you haven’t done so yet ??