Author here. The query format is (sadly) server dependent. For a ninja domain, use `whois.nic.ninja` as the server, and don't use the 'domain somedomain' query syntax.

    whois -h whois.nic.ninja domains.ninja

Normally the server would tell you the syntax it supports with `whois -h whois.nic.ninja help`, but whois.nic.ninja doesn't support `help` either.

See https://certsimple.com/blog/junk-free-whois

I really like the Debian version of whois because it solves this problem by automatically picking the correct server based on the query (even for .ninja) and following referrals to a whois server with more details.

https://packages.debian.org/stable/whois

Rad. Did some clicking around, here's the upstream https://github.com/rfc1036/whois

Thanks! Also came across gwhois.org that seems to take a novel approach to the problem too.