This is a gimmick service developed to be a fun little thing for the Go community. The idea hit me when a fellow developer made a joke about the cascading errors in Go and thought that it would be nice to have leaderboards, an API, badges, etc. Other requests/proposals for the project are things like GitHub bots that do automatic PRs with the badge in the README file of Go projects.
You can use the service at errnil.cpl.li or obtain it yourself using go get cpl.li/go/errnil/cmd/errnil. Note that the service also has an API! (more on that at a later time).
Considering this project isn't anything too serious, I am not writing any documentation for the code, any contribution guide, etc. It's a fairly simple and standard Go project.