Edge Dev Title Bar Customization

Hello,

I am wondering how I am able to customise the XAML code for Microsoft Edge's Title bar. In the old Edge, the title bar had an acrylic effect. I know Microsoft has released documentation for how to add this to custom apps but I'm wondering what files I would need to change to make the title bar in Edge Insider have an acrylic effect, and what code would I use?

Thanks!