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;[1] compton is, in turn, a fork of xcompmgr-dana, forked from xcompmgr.[2] [3] [4]
Picom can be configured using a config file which in most systems is located at $XDG_CONFIG_HOME/picom.conf. However, picom can also be made to start 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 -b flag is used to start it as a background process.[5]