It's an open source media centre application - used to be called XBMC. The illegal stuff are plugins for the software. I haven't used it since it was XBMC, quit

It's an open source media centre application - used to be called XBMC. The illegal stuff are plugins for the software. I haven't used it since it was XBMC, quite a few years ago, but I imagine you could definitely plug things like Popcorn Time into it.