@trogdor
6.4E is a module by John Erwin for the
6e Game Jam. The jam is for marginalized creators to use Jared Sinclair's PbtA system
6e (which is kind of a speculative next-gen D&D-like) as a jumping-off point to explore how they'd like a D&D-like game to be. 6.4E, in particular, is an addon for using 4e-like powers in 6e.