A Raspberry Pi "HAT" or Hardware Attached on Top is a simple upgrade component you can add to compatible models of Raspberry ...
For remote administration, though, a virtual KVM is needed, and although these solutions are pricey it’s possible to build one around a Raspberry Pi for a ... that the PiKVM hat won’t work ...
Right now, though, it’s possible to build all of this on your own without the hat, and is part of what makes the Pi-KVM impressive, as well as its very low cost.