@Peter2. Thanks for posting your question. The script.php file is the only file not being used or installed in the zip file. It’s empty anyways, so it is not important. The icons folder is copied to the Joomla’s media folder, if I recall correctly. Language files are copied to Joomla’s language folder.
Joomla’s system does not copy all the files in the zip file to the module’s folder. This is how Joomla works. There is nothing wrong, and being free has nothing to do with where the files are located.
I think the language tag for German is “de-DE”. The language INI files related to German should be installed in