This might seem like a weird feature to some that have not used a 3D printer before but a 3D printer needs another board to control the 3D printer controller board. Most people plug the 3D printer into their computers or laptops and run prints from there, this ties up the machine until the print is done. Then those users learn about running either Repetier Host/Server or OctoPrint/OctoPi on a Raspberry Pi, a low power open source computer. Adding this allows for uploading prints via the web. What you wind up with is either a mod to the printer or a bunch of wires and a Raspberry Pi consuming a desk. This is why the the Raspberry was built into the printer itself as a standard feature.
Adding a Raspberry Pi into the build
The choice to use a Raspberry Pi for this printer was base on it wide use and there were already images pre-built, making things easier.
Software for the Raspberry Pi
Between Repetier Server and OctoPrint, which seem to be among the more popular, Open – Source was kept in mind during this project. Repetier Server has a great free offering, however that offering is minus a couple of features that makes using OctoPi and Octoprint together and easy choice. Both have a good web interface, Repetier Server, can manage multiple machines very well with the web interface. OctoPrint has plugins and an active community supporting those plugins. One plugin that makes printing from any browser, simple, is Slicer. This plugin allows you to manulate STL files and slice them with either Cura or Slic3r.