In short, Electron is a runtime which is used to create desktop HTML5 applications. Under the hood, it’s running Chromium Content Module and Node.js runtimes. If your Ext JS webapp works in Chromium, it will also work within Electron web app. The impact of your Ext JS web app working in Chromium is that there is no need to test your applications on older versions of Internet Explorer, which lack modern HTML5 capabilities. Electron’s website lists numerous popular desktop applications you have probably used without realizing they are in fact an HTML5 application.