Clipper chip datasheet?

[mtal]

I've taken an interest in this little guy recently and I've managed to
find a fair bit of information in the form of retrospectives and a few
academic papers, but nothing more technical. Considering it's been
defunct for decades I'm surprised datasheets and manuals aren't easier
to find online (or maybe it's just me?). Does anybody happen to know
if/where any such material can be found?
Thanks.