What do the TargetFramework settings mean in web.config in ASP .NET MVC?

Question

One of our ASP.NET MVC 5 web applications has the following web.config settings:

Answer 1

As per my understanding is being suppressed by since httpRuntime gets translated to following

So above setting is probably due to some misunderstanding or a bug if done by VS directly which I don't believe is true.

To understand how this setting and all other related stuff means this blog titled All about written by a Microsoft employee might help you. But the gist of it is;

The .NET Framework (including ASP.NET) strives to maintain near-100% compatibility when an existing framework is updated on a machine. We try to ensure as much as possible that if an application was developed and deployed against .NET Framework 4, it will just continue to work on 4.5. This normally means keeping quirky, buggy, or undesirable behaviors in the product between versions, as fixing them may negatively affect applications which were relying on those behaviors.