Newnigma2 is an operating system based on Linux for
satellite receivers / set-top boxes developed by Dream.

Evolution

History of Linux-based firmware images for satellite receivers
History of Linux-based firmware images for satellite receivers / set-top boxes

OpenEmbedded (OE) is the underlying framework of the base system.

Enigma2 is the main application for satellite receiver related features like
handling the channel list, showing the electronic program guide (EPG), etc.

Firmware

Yadi
Yet another dbox2 image
(listed for historical reasons)
http://dboxjffs2.sourceforge.net/
openATV
The first version of openATV was based on OE1.6.
This firmware runs on hardware of other brands too.
https://www.opena.tv/
opendreambox (DreamOS)
This is the official firmware for the Dreambox.
Since version 2.5, opendreambox is also called DreamOS.
https://dreamboxupdate.com/
https://github.com/opendreambox/
newnigma2
https://newnigma2.to/

Hardware

Dreambox
https://dreambox.de/