Silverlight
Silverlight is a deprecated Microsoft framework for building rich internet applications (RIAs) that run in web browsers via a browser plugin. It enabled developers to create interactive media experiences, animations, and desktop-like applications using .NET languages like C# and XAML for UI markup. It competed with Adobe Flash and aimed to deliver high-performance multimedia content across platforms.
Developers should learn Silverlight primarily for maintaining or migrating legacy applications built during its active period (2007-2012), as it is no longer supported or recommended for new projects. It is relevant for understanding historical web technologies, handling codebases in industries like media or enterprise that used it for streaming video or interactive dashboards, and transitioning such applications to modern alternatives like HTML5 or Blazor.