I don't know this is intended or not.
When I save a game without zipped, simutrans add "/" to folder path on save/load window like "pak/".
This has a little problem because list will be sorted by path name.
dataobj\loadsave.cc:96-
if(is_zipped()) {
gzprintf(fp, "%s%s%s\n", SAVEGAME_VERSION, "zip", this->pak_extension);
}
else {
fprintf(fp, "%s%s%s\n", SAVEGAME_VERSION, mode == binary ? "bin" : "", pak_extension);
}
zip => "this->pak_extension"
bin => "pak_extension"