Presumably because it hasn’t yet been published?

The only write-up at the moment is my blog post, hopefully that changes in the coming weeks.

It seems this is still extremely early in the process. There is an apparent finding that was shared. Evidence which would be the basis for a paper is "being reviewed by linguistics experts at Rutgers and Cambridge". So they are trying to do the right thing by talking about what they believe they have done but holding off publication and serious claims until later. The general idea that written forms can be categorized by systems built with Claude could be applied to other as yet undecipherable languages could be used by other interested investigators just with what is discussed here.

You can use Claude, like the author, to reproduce the result.