Probably sudden reduction in profile or outright disappearance from the public view of the prominent experts in the area, as they are recruited to work on the more clandestine research.

My answer to part of this question is "it's not at all obvious that it's useful to pay attention too overtly to this sort of thing, especially to the degree of a tracking-website, because the government would just notice and that take some sort of different action instead."

(I'm not sure it's *not* useful either, just that this may be a somewhat anti-inductive domain)

Would having this information actually be beneficial. Perhaps it'd be good for us to know what is going on, but it might be negative for certain governments to know about this as it might increase the chance of an AI arms race.

It would be easy to hide it within another public project that plausibly would need those researchers and experts. Announce a mission to build a moon base, or put humans on Mars. Part of that will need advanced robotics and AI, so now you have a Black Budget project hidden within a public project, and a perfect cover story. Plant 42 has been cranking out Black Budget surprises for decades, though they don't need a cover story, everyone knows it is a "secret" aerospace R&D and manufacturing facility.