The archive should contain a file info.txt with short description of what was changed, who created it. Also, if possible, names of authors of original files and sources, permitions etc. The structure of folders and files inside it should be ready to unpack directly into main directory of MaSzyna, to simplify the installation.
Also, keep in mind the licence of MaSzyna: once you add something, it can be distributed only for free and everyone else can modify anything. This applies only for MaSzyna purposes and not for other ones. (However this doesn't really matter in case of timetables, but perhaps someone else may be interested.)