PolicyKit is a toolkit for defining and handling authorizations.
It is used for allowing unprivileged processes to speak to privileged
processes.

Systemd is a system and service manager, compatible with SysV and LSB
init scripts for Linux. systemd provides aggressive parallelization
capabilities, uses socket and D-Bus activation for starting services,
offers on-demand starting of daemons, keeps track of processes using
Linux cgroups, supports snapshotting and restoring of the system state,
maintains mount and automount points and implements an elaborate
transactional dependency-based service control logic. It can work as a
drop-in replacement for sysvinit.

A tree-like directory listing program with dircolors support

Udev creates and removes device nodes in /dev for devices discovered or
removed from the system. It receives events via kernel netlink messages
and dispatches them according to rules in /lib/udev/rules.d/. Matching
rules may name a device node, create additional symlinks to the node,
call tools to initialize a device, or load needed kernel modules.