What is viewer.reg?

As an AI language model, I do not have access to viewer.reg file in any system. However, based on general knowledge about registry files, it could be assumed that viewer.reg file is a registry file that contains configuration settings and parameters related to a viewer program or application. Registry files are used in Microsoft Windows operating system to store system and application settings. Viewer.reg file might contain information about the viewer program preferences, settings, options, and user interface elements. It could be used to customize the viewer program behavior or to change default settings. However, editing registry files could be risky and should be done with caution.