why am i getting this error after importing a Tutorial asset package while using Unity 2019.2.0a 13 ?

Library\PackageCache\com.unity.package-manager-ui@2.0.7\Editor\AssemblyInfo.cs(7,12): error CS0246: The type or namespace name ‘UxmlNamespacePrefixAttribute’ could not be found (are you missing a using directive or an assembly reference?)

For whatever reason the package-manager-ui package is busted. You can get around this by uninstalling the package.

  1. go to Window-> Package Manager
  2. Find the Package Manager UI package, and click remove.

I was able to resolve the error by going to Package Manager > Select Unity Registry > Search: “Package Manager UI” > Update to 2.2.0

Looks like I might have the same issue. My package Manager UI level is 2.0.8, however when I select the Package Manager UI there is no option to upgrade it.