FreeBSD (17 ~): ncal -M 2016
ncal: illegal option -- M
Usage: cal [general options] [-hjy] [[month] year]
       cal [general options] [-hj] [-m month] [year]
       ncal [general options] [-hJjpwy] [-s country_code] [[month] year]
       ncal [general options] [-hJeo] [year]
General options: [-NC3] [-A months] [-B months]
For debug the highlighting: [-H yyyy-mm-dd] [-d yyyy-mm]