What is what is.cab?

It is a file format used for installing software on Windows operating system. CAB files (short for cabinet files) are compressed archives that contain multiple files and are typically used for distributing complex software packages. These files can be extracted and installed on a Windows device using built-in Windows tools, such as Windows Explorer or the command-line tool DISM. CAB files have been around since Windows 3.1 and continue to be used for software installation and distribution.