So, everyone would have to roll their own rendering engine… er… nice… maybe some of you here remember VRML? That was the original attempt at an open 3D standard for the web… yea… we see where that ended up. 
I would guess the rendering engine is “included” to some degree, but any frameworks and application code around it would presumably be written in JavaScript. All in plain sight for the end user.
Not sure who’s going to use it and for what. Mostly to revive the spinning corporate logo, maybe.
i think this simply will enable using opengl in the canvas html element.
i am looking forward to it. could be very useful for many things like simple product visualizations.
but it won’t really be an alternative to a full game engine like unity.
Interesting. Khronos has a history of making successful products (like OpenGL ES) and epic failures (like OpenGL). We’ll see how this one turns out