The package looks for LuaTeX regardless of its mode and provides the switch \ifluatex; it works with Plain TeX or LaTeX.
The package is part of the oberdiek bundle.
The author is Heiko Oberdiek. The package is Copyright © 2007,2009,2010 Heiko Oberdiek.
License: lppl1.3 Version: 1.4, dated: 2016-05-16 Catalogued: 2016-05-18