Thank you.
I have found that the German central government has a kind of ‘War Graves Commission’ operating under law, whose duty it is to maintain war graves.
Their website has some brief details of the Seelow cemetery:
Come the end of the war (and maybe not surprisingly) the Russians cared little for German war dead, millions of whom lay in Russia, Belarus and Ukraine, let alone the dead within Germany itself. Their only effort was to order the local German population to scour the surroundings to find bodies, not through any moral duty but rather because they feared disease. What the locals then did by way of burying or disposing the corpses was up to them. From the German side, the locals were struggling anyway, surviving or not in a totally shattered world.
There’s an interesting story about the ‘clean up’ in relation to the Halbe Pocket cemetery, the largest cemetery on German soil, which I’ve read about. I hope to see Halbe and the cemetery on my return journey.