Microsoft Web Framework is described as 'MWF is a system that allows site authors to consider how best to tell the story of Microsoft products and services with confidence that the modular pieces will support and work together' and is an app in the Development category. There are more than 100 alternatives to Microsoft Web Framework for a variety of platforms, including Online / Web-based, Self-Hosted solutions, Mac, Windows and Linux. The best alternative is Bootstrap, which is both free and Open Source. Other great apps like Microsoft Web Framework are Vue.js (Free, Open Source), React (Free, Open Source), AngularJS (Free, Open Source) and Bulma (Free, Open Source).
Structure is a declarative, Flexbox based grid framework. Structure defines layout using non-standard attributes on elements. (If you have used frameworks like AngularJS, you have already gotten some exposure to declarative syntax and non-standard attributes.)