This page lists a few things that could still be done and that nobody is actively working on. It is not exhaustive at all and if you want to work on something that is not on this list, that's absolutely fine - maybe drop us a line on the XMLUnit general list so we can avoid duplicate or wasted effort.
- work on the open issues
- additional hamcrest matchers
- additional NUnit constraints
- build ISource from objects via XmlSerializer
- .NET Core support (without breaking the .NET 3.5 builds)