The Xcode Workspace Format standard was defined by Apple. Files with .xcworkspace extension are Developer Files. The Developer Files category has 1205 various formats. Apple Xcode software is recommended for managing .xcworkspace files. When an .xcodeproj file is created, Xcode makes an .xcworkspace file in it automatically. To open a .xcworkspace file select File -> Open in Xcode on macOS. Opening a .xcworkspace file restores the project and perspective.
Most .xcworkspace files are not compatible, needing different apps. Apple made the format and Xcode program. An .xcworkspace file was likely made in Xcode. Tools to use with .xcworkspace files: Opener, Converter, Viewer. The .xcworkspace extension is for Xcode, the macOS and iOS development tool. It stores workspace settings for a project. Xcode uses these commonly.
Tips on opening .xcworkspace files and programs that support them:
To open, use Xcode on macOS. Opening restores project and perspective. So .xcworkspace files container Xcode .xcodeproj projects.