The CIMViewer can be used to examine layer and map (2D or 3D) CIM definitions in Pro. Select a layer, map, or scene in the TOC with the viewer open and its CIM definition will be loaded into the XML Editor. The XML Editor uses the AvalonEdit control which provides syntax colorization and formatting. Cut, Copy, Paste, and XML Validation have been added in the Add-in so the XML editing experience is reasonably functional though not as rich as a fully fledged commercial editor like XML Spy. However, it is a simple task of copy/pasting the CIM XML into a commercial editor if that level of XML manipulation is desired.
The Save button will save any changes you make back to the layer, map, or scene whose CIM definition you loaded. However, there is not much of a safety net to protect you against making really bad xml or other inadvertant mistakes so use the
Save functionality with caution. The primary use of the CIM Viewer is to allow you, the developer, to decipher the inner workings or "guts" of the CIM and how it affects the configuration of your Pro project at any given point in time. In other words, it is a learning or educational tool that can be used to help you in your Pro development efforts and is not a customization or configuration tool.
The CIM Viewer is at https://github.com/Esri/arcgis-pro-sdk-cim-viewer
You will need the AvalonEdit and Extended.Wpf.Toolkit NuGets to compile and build the CIM Viewer. The NuGet package.config is included with the project so these should download automatically when you attempt to build. If your Visual Studio is not configured to automatically download and install NuGets you can use the Visual Studio NuGet Package Manager to do it by hand.