Thanks for checking this. Very few laptops support this, and its badly documented. But it's IMHO the difference between good and superb Linux support.

Run sudo acpid, will start the daemon in the background.

Then run acpi_listen. It will block waiting for events. E.g. if you press media keys, un/plug the adapter, etc you should start seeing events. One per line.

Just leave it running on battery for a while. Hopefully it has events at 1% or 5% discharge intervals. Or at least for critical battery levels, when you cross the 10% or 5% level. Emergency thresholds can be usually controlled through a variable in sysfs.

These events are needed to write udev rules that get fired by the kernel. Thanks!