Binary package “nx-x11proto-composite-dev” in ubuntu bionic

nx-X11 Composite extension wire protocol

 NX is a software suite which implements very efficient
 compression of the X11 protocol. This increases performance when
 using X applications over a network, especially a slow one.
 .
 This package provides development headers describing the wire protocol
 for the Composite extension in nx-X11, used to let arbitrary client
 programs control drawing of the final image.