XUL Layout is gone
This was basically Electron before there was Electron.<p>It was hoped that other people would follow the Mozilla Suite's (before Firefox, Mozilla's standard distro was an application suite containing a browser, email reader, chat client, and HTML editor) example and use JavaScript, XUL, and XPCOM to build cross-platform desktop applications. The last of those, XPCOM (Xross Platform COM), was Mozilla's take on Microsoft's Component Object Model, where you would write lower-level components in C or C++ (using the NSPR, Netscape Portable Runtime) that were callable from JavaScript<p>Unfortunately, virtually no one outside of Mozilla adopted the XUL/JS/XPCOM stack. One of the few I remember was ActiveState's Komodo IDE.<p>I still regard it as a huge missed opportunity for Mozilla.