I've moved your question to the Developer forum, since the LibDev Toolkit is only available to developers.
Which version of the LibDev Toolkit are you trying to install? If you unzip the file, you'll see mostly platform independent things - documentation, sources, etc. Under the Tool folder you'll find OS X and Windows version of the XML converter as well as documentation for it. There is nothing to install, just run as documented.
One of the forum moderators • AC 26 USA and earlier • macOS Ventura 13.2.1, iMac Pro 10-Core, Radeon Pro Vega 64