i3's interprocess communication (or ipc) is the interface i3wm uses to receive
commands from client applications such as i3-msg. It also features
a publish/subscribe mechanism for notifying interested parties of window
manager events.
i3ipc-python is a Python library for controlling the window manager. This
project is intended to be useful for general scripting, and for applications
that interact with the window manager like status line generators, notification
daemons, and pagers.