.in files standard

ubuntu@1af1b644de0a:~/xeus-zmq/example$ cat share/jupyter/kernels/my_kernel/kernel.json.in 
{
    "display_name": "my_kernel",
    "argv": [
        "@CMAKE_INSTALL_PREFIX@/@CMAKE_INSTALL_BINDIR@/@EXECUTABLE_NAME@",
        "-f",
        "{connection_file}"
    ],
    "language": "python"
}