Thank you for a detailed reply, Florian.

Unfortunately I don't have much time for this now.
The point to define helper explicitly is to name the parametres and that's why:
* `string` is actually the string-identifier in the `i18nMessages` namespace system, is of course mandatory
* `content` is optional and is used in for dynamic content, which we insert into `message`. The `message` is the fixed variable name in the handlebars template - I mean that we define it here and `{{message}}` should be used in the template to output dynamics.

Sorry, maybe that's just because of my coding level.
I will return to this as soon as I have time.