There are a bunch of tools that let you view a x509 certificate. Now I have one. I mostly made it for myself. It's only distinguishing feature is that it will include human readable names for CT-logs. I was trying to figure out what was going on with CT-logs in the Let's Encrypt staging environment. Using openssl to get the hex log-id, then converting that to base64, then searching for it in the list of known logs was getting tedious, so I made this tool to do it for me. It accepts PEM or DER encoded certificates.