Linux

The groups the user is member of define what activities the user can perform.

Pacman is a package management utility that tracks installed packages on a Linux system.

the actual init system being used.

The Linux kernel supports EFISTUB booting which allows EFI firmware to load the kernel as an EFI executable.

The kernel is the core of an operating system.

KVM, Kernel-based Virtual Machine, is a hypervisor built into the Linux kernel.

A power-on self-test (POST) is a process performed by firmware or software routines immediately after a computer or other digital electronic device is powered on.

A hypervisor (or virtual machine monitor, VMM, virtualizer) is a kind of emulator; it is computer software, firmware or hardware that creates and runs virtual machines.