The consensus seems to be that this was just a symbol the military chose randomly to draw on the military vehicles going to Ukraine to distinguish them from Ukrainian vehicles most of which are also Soviet-made. Now it came to mean support for the "military operation" in Ukraine.
what does Z means anyways?
Zorro.
It's a joke. I don't actually know.
In GenZedong or in Russia?
Russia
The consensus seems to be that this was just a symbol the military chose randomly to draw on the military vehicles going to Ukraine to distinguish them from Ukrainian vehicles most of which are also Soviet-made. Now it came to mean support for the "military operation" in Ukraine.