Image build up
From OpenPLi Wiki
An image consists of two parts: the operating system, and the enigma2 application. The operating system is based on OpenEmbedded Linux (a distribution especially for embedded devices), which is compiled based on building recipes.
You have image builders who maintain those build recipes themselves (OpenPLi, VTI, DMM), and you have builders who use the OE-Alliance recipes (ATV, Blackhole, Opendroid, OpenEight, HDF, OpenFr, SPA, VIX, Teamblue) and only maintained an own version of Enigma2.