Clever people have made their own tweaks of the Kodi base build to improve performance. SPMC for example, is a variant of Kodi developed specifically for android boxes (kodi, as you know will run on android, windows, Linux, ios, os). Droidbox have taken SPMC and rebadged it as DBMC, possibly adding their own optimisation for T8 boxes. The names like isengaard, helix, gotham are naming conventions for major kodi base releases (in this case, 15, 14, 13 respectively). There will be something named after "j" for kodi 16 which is already in beta testing.