What is the „Simplicity Commander“ and where can I get it from?

The Simplicity Commander is a utility that provides a graphical user interface (GUI) and command line interfaces (CLI) to the debug features of an EFR32-based device. We highly recommend using it in conjunction with our Lyra (22) and 24 series. It for example allows you to reprogram the Lyra module, update development board firmware, and lock, or unlock debug access if needed. This tool is part of the Simplicity Studio 5 Software & IDE by default. A portable version for Windows, GNU/Linux and macOS can also be found at https://www.silabs.com/developers/simplicity-studio#commander.