This type will be used for representing possible states of a change review across different code review systems (GitHub PRs, Gerrit CLs, and other custom changes). The possible values are largely based on the code review conventions set up for the Go project. They are described at https://groups.google.com/d/msg/golang-dev/YU56eKYiXJg/K1CkXo7Iy0gJ. This is a starting point, the values may change if compelling reasons to do so are discovered.
At this time, the go.mod file specifies only the module path, and nothing more. In the future, it can be expanded to specify additional information, such as the required modules and their versions, and the expected Go language version. This will be considered after some time passes, and the long-term implications of doing so are better understood.