yesterday I was very boored. So I thought of what I could do. Instead of doing usefull things I took the next map.gbx file I could find and played arround withit . Next to the hieroglyphs in the code of an map.gbx I found some normal letters defining the author times, the environment and the size of the map. There were many possibilitys for a boored Frank to spend his time with.
Things I tried: Cheat author times better
put 64x64 on a valley map
add random letters and watch what happens
The problem is: No matter what I do (even if I change the settings, save them, then open the file again, reset the settings and save again) after the map is changed in the code it is no longer openable in Maniaplanet.
Not even If I changed an author time in a gbx file maniaplanet allowed me to open the map. (First it was 22000 and I changed it to 21000) but there was no reason why it should not work.
Well, in result I completely failed to do sth with it. But other people who might understand that could do many things with it.
So If you are boored one day (and you are not such a gbx-noob like I am) - do the same like me

not... most propably not....