Is there anything we know about the "Marble alien" from MIB 1997

Y’know, funnily enough that’s the only bit that really stayed with me. It was a long doc, I seem to remember it being 90 pages long or something, and it covered a lot of ground. In-universe history and stuff, it talked about the treaty (?) that served as the foundation for MIB’s role in policing and monitoring alien traffic on Earth, which I don’t remember the movies spending a lot of time on - understandably! The most interesting part, to me at least, was the section talking about the themes that make an MIB story an MIB story. That felt like a writerly dissection breaking down, for future writers, what purpose stories needed to serve to be considered “MIB” stories. Which sounds pretty prescriptive, but it wasn’t laying out specific plot elements or mandatory scenes etc., it was more about the spirit of the story, the tone, the message. I’m having to wrack my brains to remember more, but I think the larger universe being hidden in plain sight was part of it too? Which makes sense looking at those movies, where the aliens are often disguised in urban environments, or masquerading as humans. It’s like cosmic horror but with a positive slant - “the universe is incomprehensibly big and I don’t understand anything but I still matter because the small affects the large just as much as the large affects the small”. That’s roughly the intended vibe of an MIB story. And if you go back and watch any of those movies, you’ll see that concept weaved throughout the films in ways both subtle and direct.