Since version 2.1.0 of BwPostman there is the ability to export templates. With this You are able to transfer templates created for one installation to another.
After activating the checkbox of the desired template at the list of templates and a click to Export template a file is created that contains the template in a installable manner. When this process has finished, a message with a download button is displayed. This file also is stored at
and can be downloaded (or deleted) from there as well using the Media-Manager of Joomla!®.
The file name contains the ID of the exported template, because the ID is surely unique, there are no two templates with the same ID. The title of the template cannot be used (quite alone).
You don't have to conserve the file name, the import of the template works with every file name.