It is a few paragraphs down on the linked page:

> The following features are known not to work: suspend, display out on the USB-C ports (HDMI works), and Thunderbolt/USB4. Additionally, power consumption may be higher than expected (not very relevant for a desktop); we have set conservative limits for max speaker volume for safety reasons; and shutdown/reboot are flaky (you can just use the power button anyways). Every feature not listed here works and has been tested.