Picom is a lightweight standalone compositor created for the X Window System. It is a fork of compton, created because compton wasn't being actively maintained; compton is, in turn, a fork of xcompmgr-dana, forked from xcompmgr.
Picom can be configured using a config file which in most systems is located at <code>$XDG_CONFIG_HOME/picom.conf</code>. However, picom can also be started with a custom config file using the following options:
Picom has multiple configurations in which it can be run, however in most instances, when using it in conjunction with another window manager, the <code>-b</code> flag is used to start it as a background process.