The Keys System
Several years ago, when I was still working in the Core department at Opera Software, I became aware that the Information Services team had started using a web-based tool to manage SSH key access to root accounts on their servers (I discovered this when I needed to upload my key there to get access to a server that was shared with them).
A few reorganizations and ownership shifts later, I found myself in the team that owned this tool, known only as "the Keys system", or by its hostname "keys".
In November 2013 I embarked on a project to rewrite the Keys system, adding the ability to manage more than just the root account, and improving the user interface. Other features were added later such as group access management, SSH access options, and immediate syncing. It soon became quite well-liked within the company as a tool for people to manage access to their servers.
We've been hoping to open source this for quite some time, and after the successful open-sourcing of our PowerDNS management tool (which was actually developed after the Keys system and shares a lot of core code in common) we've been getting ready to go ahead with this one.