Component:

A component is a piece of hardware or software that is used used to control devices. The component selector can be used to display devices controlled by a specific piece of hardware or software; for example all devices controlled by CBUS, or all the cameras managed by Harmony CCTV Server.

'Components' automatically add themselves to the component selector when an extention is installed. For example when an X10 extention is installed all the X10 components will appear in the component selector in Harmony.