Why a new namespace is created, when I upload a translation file?
When importing a translation file in the Control Center view, after having selected the file, you'll see a screen like this:


By default the "Target namespace" is set to the name of your file.
If you want to import the translations to a specific namespace, make sure you select the appropriate namespace:

Alternatively, you can import the file directly in the correct namespace via the Focus view or in the Global view by previously selecting the correct language and namespace.