/etc/groonga/ is in groonga-httpd 6.0.1-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/etc/groonga/httpd/
/etc/groonga/httpd/client_body_temp/
/etc/groonga/httpd/fastcgi.conf
/etc/groonga/httpd/fastcgi.conf.default
/etc/groonga/httpd/fastcgi_params
/etc/groonga/httpd/fastcgi_params.default
/etc/groonga/httpd/fastcgi_temp/
/etc/groonga/httpd/groonga-httpd.conf
/etc/groonga/httpd/html/
/etc/groonga/httpd/html/50x.html
/etc/groonga/httpd/html/index.html
/etc/groonga/httpd/koi-utf
/etc/groonga/httpd/koi-win
/etc/groonga/httpd/logs/
/etc/groonga/httpd/mime.types
/etc/groonga/httpd/mime.types.default
/etc/groonga/httpd/nginx.conf.default
/etc/groonga/httpd/proxy_temp/
/etc/groonga/httpd/scgi_params
/etc/groonga/httpd/scgi_params.default
/etc/groonga/httpd/scgi_temp/
/etc/groonga/httpd/uwsgi_params
/etc/groonga/httpd/uwsgi_params.default
/etc/groonga/httpd/uwsgi_temp/
/etc/groonga/httpd/win-utf