The mod Project Cybersyn (2.0.30) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event cybersyn::on_object_destroyed (ID 175)
...n__/scripts/mod-compatibility/se-elevator-connection.lua:79: attempt to index field 'se_elevators' (a nil value)
stack traceback:
    ...n__/scripts/mod-compatibility/se-elevator-connection.lua:79: in function 'on_object_destroyed'
    __cybersyn__/scripts/main.lua:782: in function <__cybersyn__/scripts/main.lua:781>

This crash occurs in the editor, when deleting practically anything that's connected by wires (red or green). I don't have the Space Exploration mod (active or even downloaded), so there's no reason for the Space Elevator compatibility script to run at all. As this does not happen in regular play, I have to imagine this is something specific to the map editor.

edit
Addendum: It seems like this occurs with anything that has been connected to the signal network, even after it's disconnected. I was able to reproduce this bug by connecting a container to the network, disconnecting it and deleting it. Seems like the "on_object_destroyed" function in main is triggering when it shouldn't be.