Maybe as some first contact protocol, by dropping the rock outside a candidates solar system. But again, i'd expect them to have so much better ways to observe.
We humans really have a tendency to see pattern in things. Even after having having seen the decompiled game code being basic RNG, a part of me was still looking for ways to improve my drop chance by me doing things slightly different :D
I really think we are limited by our imagination and anthropomorphism. A civilization a million years ahead of us in development is likely capable of things we can’t even imagine.
I always like to remind myself that our own civilization is at most only 10k years old. If we survive, I can’t imagine what we would be like in 10x more time.
If you were to travel to the 1600s and tell people that we have generative AI, spaceships, and smartphones, their brains wouldn't be able to comprehend it.
"expect it to slowly return to somewhere "civilized"." - this one looks good.