Zammad translations are managed exclusively via translations.zammad.org.
You are welcome to contribute. Please get a free account there if you want to do so.
Any pull requests modifying translation files directly will be rejected.
Zammad text modules are automatically imported when the first admin user is created, according to this user's language. This is just meant to provide for a smooth start with some existing helpful text modules. They can be modified later on; no subsequent import from the example files will be performed.
Feel free to send pull requests to add more helpful examples to existing files or even files for new languages.