$ openssl x509 -in cabundle.crt -text -noout
$ openssl x509 -in /usr/share/ssl/certs/ca-bundle.crt -text -noout

Technical notes, and other ideas.
$ openssl x509 -in cabundle.crt -text -noout
$ openssl x509 -in /usr/share/ssl/certs/ca-bundle.crt -text -noout