The Registration
Data Access Protocol is meant to replace
Whois.
In short: Whois is plain text. RDAP is JSON via HTTP/HTTPS.
Below a DIY backport from Debian 13 / Trixie to Debian 12 / Bookworm;
rdap_0.9.1-3~bpo12+1_amd64.deb
rdap-dbgsym_0.9.1-3~bpo12+1_amd64.deb
And one for Debian 11 / Bullseye;
rdap_0.9.1-3~bpo11+1_amd64.deb
The usual disclaimers apply.