a lightweight, standalone composite manager for X, suitable for use with window managers that do not natively provide compositing functionality and a fork of xcompmgr-dana.
Compton itself is a fork of xcompmgr-dana, which in turn is a fork of xcompmgr. See the compton github page for further information. Compton in particular is notable for fixing numerous bugs found in its predecessors, and as such, is popular due to its reliability and stability.
Numerous additional improvements and configuration options have also been implemented, including a faster GLX (OpenGL) backend (disabled by default), default inactive/active window opacity, window frame transparency, window background blur, window color inversion, painting rate throttling, VSync, condition-based fine-tune control, configuration file reading, and D-Bus control.
Source: ArchWiki