The default installation path of the old launcher on linux was ~/StarMade (~ is the path to the personal folder)
The default installation path of the new launcher on linux (both 32 bit and 64 bit) is ~/.config/StarMade .
This is a slight problem, as the folder .config should only contain configuration files, and no entire installations. As such, there MAY be complications with some cleanup processes erasing the installation, as the result of the improper use of that folder.