XamarinDevDays/Demos/app-myweather/MyWeather.UWP/MainPage.xaml

<forms:WindowsPage
    x:Class="MyWeather.UWP.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:MyWeather.UWP"
     xmlns:forms="using:Xamarin.Forms.Platform.UWP"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">
</forms:WindowsPage>