This Fiddler plug-in will simulate your title's behavior due to lack of connectivity to various Xbox Live services. For example, you can test your title's behavior if Rich Presence is returning 429s, or if all services are returning 503s.
There are important files that Microsoft projects should all have that are not present in this repository. A pull request has been opened to add the missing file(s). When the pr is merged this issue will be closed automatically.