Exporting (iCloud) Keychain and Safari credentials to a CSV file
Update (October 2021)
Exporting password + one-time code data from iCloud Keychain is now officially supported in macOS Monterey and Safari 15 (for Monterey, Big Sur, and Catalina). You can access it in the Password Manager’s “gear” icon (System Preferences > Passwords on Monterey, and Safari > Passwords everywhere else), or via the File > Export > Passwords... menu item). You shouldn't need to hack up your own exporter anymore.
Original, Obsolete Content (2014)
After my dad died, I wanted to be able to have access any of his online accounts going forward. My dad was a Safari user and used iCloud Keychain to sync his credentials across his devices. I don’t want to have to keep an OS X user account around just to access his accounts, so I wanted to export his credentials to a portable file.