/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/ is in ruby-amqp 0.9.5-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/cacert.cer
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/cacert.pem
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/certs/
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/certs/01.pem
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/certs/02.pem
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/index.txt
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/index.txt.attr
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/index.txt.attr.old
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/index.txt.old
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/openssl.cnf
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/private/
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/private/cakey.pem
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/serial
/usr/share/doc/ruby-amqp/examples/tls_certificates/testca/serial.old