libnx-x11-dev 2:3.5.99.23-1build1 (arm64 binary) in ubuntu focal

 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 of the libNX_X11 library (a
 libX11 drop-in replacement used by nxagent).