@carl The HTML is valid HTML5, both <html> and <body> are optional. Anyway it doesn't matter what I have there, its always a blank page.
Someone on Twitter told me though that it works for them on their Ubuntu and with Qt installed via the installer from the Qt website.
@carl I tested it now on Ubuntu at work and it works just fine, so it's something with my Arch installation.
Linux geeks doing what Linux geeks do...