No need for dummy monitors, to disable the forced automatic sleeping behaviour when closing the lid just run
sudo pmset -a disablesleep 1No need for dummy monitors, to disable the forced automatic sleeping behaviour when closing the lid just run
sudo pmset -a disablesleep 1
I remembered that you used to need a kernel extension for this because the behavior is hardcoded without an option. Glad that they added a proper option so you no longer need to do this.