Microsoft ASP.NET and Web Tools - Visual Studio Marketplace

Provides web tooling updates for ASP.NET. It also enables you to try .NET Core 1.0.1 in Visual Studio 2015 (.NET Core tools are preview only).

Tooling support for ASP.NET for .NET Framework
Preview tooling support for .NET Core and ASP.NET Core (1.0.1)
Deploy your ASP.NET and ASP.NET Core applications to on premise IIS Servers and/or Microsoft Azure
And many other features…

Visual Studio 2017 is the first version of Visual Studio that offers supported tools for .NET Core development.

This update contains changes as described in KB4339279.