A RBZ file is a plugin used by SketchUp, a 3D modeling program used for computer-aided design (CAD). It stores one or more Ruby scripts (.RB files) that are compressed with .ZIP compression. RBZ files are useful for reducing the size of SketchUp plugins when distributing and installing them.

SketchUp 8 was the first version to allow compressed RBZ plugin files. You can search and download SketchUp plugins from the "Extension Warehouse" online repository by selecting Window → Extension Warehouse. In the Windows version of SketchUp you can install RBZ plugin files by following these steps: Choose Window → Preferences. Select "Extensions." Click Install Extension and choose your RBZ file from the open dialog. In the macOS (OS X) version of SketchUp you can install RBZ plugin files by following these steps: Select SketchUp → Preferences. Choose "Extensions." Click Install Extension and choose your RBZ file from the open dialog. NOTE: RBZ files can be restored to the original Ruby scripts by unzipping them.