Gantry Prime is a standalone Gantry 5 installation which allows developers and testers to access all the features in both administration and the site without the overhead and quirks of installing and running a CMS.
The platform consists of static pages, modules and common assets as well as default configuration and layouts do display those. Themes can then be installed to this platform allowing us to run through all the predefined content, thus making it ideal development and testing platform. New sample content can be included by just adding the files, so whenever there is a new issue, we could just include a new test case and make sure all the templates from both the past and the future will never have the same issue again.
In the future Gantry Prime could also be used to showcase themes and their administration, making it possible to be used as a demo environment. Think of having a demo, where users could freely play around in the theme administration and see their changes in the theme itself. These changes could be session based allowing many users to play with the environment without messing up anything else but their own instance.