pkg is the package management tool for FreeBSD.
Manual page: https://www.freebsd.org/cgi/man.cgi?query=pkg(8)
FreshPorts listing: https://www.freshports.org/ports-mgmt/pkg/
pkg in the FreeBSD repository on GitHub: https://github.com/freebsd/pkg
pkg was the new generation (pkgng) replacement for pkg_info, pkg_create and pkg_add, which were previously used for registration of local packages and provision of remote packages.