For .NET Core 2.x, the Microsoft.NETCore.App package includes a platform manifest .txt file as well as PackageConflictOverrides MSBuild items for conflict resolution. For .NET Core 3.0, these should come from the targeting pack for framework dependent apps, and from the runtime pack for self-contained apps.

This means that both targeting packs and runtime packs need to include this data, and the SDK needs to use the data from the appropriate type of pack depending on whether the app is self-contained or not.