Zipped mod package files should be placed in "mods/" and need to contain
directory trees starting with "packages/" (or "config/"). The files from
a zip mod replace files, that exist in the original game install or add
new files.
The zip file should contain three special files:
desc.txt
Contains one line with a descriptive title for the package and ten
more optional lines with a detailed description.
preview.jpg
Preview picture for the mod. Must not exceed 128 kbytes. Aim for
512x512 pixel.
revision_n
Empty file. The "n" in the filename should be a valid integer number
instead, specifying the zip revision. Example "revision_123".
The settings menu shows the active mods in order of their priority - which
determines, which file to use, if several mod packages try to add or
substitute the same file. Zip files higher up in the list win.