Is there a Windows version?

Yes, there is now, starting from version 4.0. It has been built:

However, note that it is has not received much feedback yet (it is not regularly tested with the the validation test suite). Also, the installation manual does not describe how to setup an environment to build that version from sources (though build scripts proper are in the code tree), so development and debugging are preferrably done on Linux or similar platforms.

Any feedback is welcome, and help improving the build system for Windows even more so.

For Windows users who are somewhat familiar with the command-line, the code may also be build on the Linux subsystem for Windows, in which case the Linux installation instructions can be used, The GUI requires an X-server, which is not officially supported, but seems to work.