Check Run Reporter is the brainchild of Ian Remmel, caused by his frustration the lack of reporting tools in many populare CI frameworks and realization that GitHub supplies many underused presentational capabilities.
Ian Remmel has been formally working in software for nearly and decade and informally, nearly another decade before that.
In his time at Cisco and UrbanDoor, he became extremely familiar with legacy CI systems like TeamCity and Jenkins and if you buy him a beer, he'll happily go into exhaustive detail about their pros and cons (to be honest, it probably won’t take a beer). He's a fan of Circle CI and recently has been intrigued by Buildkite.