What is the typical file extension for a widget's designer view file in Sitefinity?

In Sitefinity, the typical file extension for a widget's designer view file is .cshtml. This extension indicates that the file is a Razor view, a part of the ASP.NET framework which Sitefinity utilizes for rendering dynamic content. Razor views allow developers to combine HTML markup with C# code, enhancing the capability to create rich user interfaces.

Using .cshtml files enables better integration within the MVC architecture that Sitefinity supports, allowing developers to easily create and customize layouts for widgets. This integration allows for more interactive and responsive web applications, which are essential in modern web development.

While .design files are commonly associated with design files in other contexts, they do not pertain to widget development within Sitefinity specifically. Likewise, .json and .xml file extensions are used for data interchange and configuration purposes, not as designer views for widgets. Thus, .cshtml stands out as the correct choice for the designer view file in the Sitefinity environment.