dropbear sshd invokation does not work

[terefang]

output:

/usr/bin # sshd --help
Dropbear SSH multi-purpose v2016.73
Make a symlink pointing at this binary with one of the
following names or run 'dropbearmulti <command>'.
'dropbear' - the Dropbear server
'dbclient' or 'ssh' - the Dropbear client
'dropbearkey' - the key generator
'dropbearconvert' - the key converter
'scp' - secure copy