Twinpack is a package manager for TwinCAT libraries with integration into the TwinCAT IDE. It enables the TwinCAT community to share their libraries and simplifies the continous integration of third-party components into TwinCAT projects.
the dialog actually shows the referenced library and not installed versions. In a Twincat context it might actually better to rename „installed“ and „install“ to „referenced“ and „add“ though
i assume, installed shows all installed version of a library, and available a list with all available versions of a library
maybe a referenced entry would be nice to quickly see which version is referenced in the project