I believe it was (or at least speculated) to be to help prevent friendly fire, as Ukraine and Russia often had the same types of vehicles, legacy of the cold war and being on relatively good terms until Maidan 2014. Also paramilitary Donbass units with random improvised vehicles and for any defecting troops or captured functional vehicles. Similar to the white armbands worn by Russian soldiers.
Sometimes the symbols have other features (like being in a circle/square) or chevrons etc. That’s probably to tell different units apart.
I believe it was (or at least speculated) to be to help prevent friendly fire, as Ukraine and Russia often had the same types of vehicles, legacy of the cold war and being on relatively good terms until Maidan 2014. Also paramilitary Donbass units with random improvised vehicles and for any defecting troops or captured functional vehicles. Similar to the white armbands worn by Russian soldiers.
Sometimes the symbols have other features (like being in a circle/square) or chevrons etc. That’s probably to tell different units apart.