nx-x11proto-xinerama-dev 2:3.5.99.21-2 (arm64 binary) in ubuntu eoan

 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 XINERAMA extension, used to use and manage a multiple-screen
 display.