Provided by: unbound_1.4.22-1ubuntu4_amd64
unbound - Unbound DNS validating resolver 1.4.22.
unbound [-h] [-d] [-v] [-c cfgfile]
Unbound is an implementation of a DNS resolver, that does caching and DNSSEC validation. The available options are: -h Show the version and commandline option help. -c cfgfile Set the config file with settings for unbound to read instead of reading the file at the default location, /etc/unbound/unbound.conf. The syntax is described in unbound.conf(5). -d Debug flag, do not fork into the background, but stay attached to the console. This flag will also delay writing to the logfile until the thread-spawn time. So that most config and setup errors appear on stderr. -v Increase verbosity. If given multiple times, more information is logged. This is in addition to the verbosity (if any) from the config file.
Unbound developers are mentioned in the CREDITS file in the distribution.