The page contains source code for the javaxt_core.dll packaged with javaxt-core. 32-bit and 64-bit version of the DLL was created using Visual Studio 6 as described here and here.
Information about the javaxt-core library, documentation, and releases can be found on the project homepage:
All JavaXT libraries are free and open source released under a permissive MIT license. This software comes with no guarantees or warranties. You may use this software in any open source or commercial project.