While Leadwerks has been out for Linux and Leadwerks is in the Ubuntu Store, it hasn't been on Steam for Linux up to this point. Barring this Kickstart-funded Linux game engine port from being on Steam came down to a technical requirement -- GCC mandating 16-bit ABI alignment. After help from Valve and Blitz Research, that issue has been overcome so Leadwerks will soon be released on Steam.
The other Leadwerks update worth noting is Blender exporter support for complying with the Leadwerks game engine formats. Blender is starting to be picked up by more game modders and format support for commercial quality games, with just recently Epic Games' sponsoring in part Blender's development.
More on the latest Leadwerks Linux improvements can be found via this Kickstarter update.