This is Google at its 1990s COMDEX/Microsoft Vapourware worst. There is no product to try, no code samples, no documentation. Just an animated GIF of what the experience may be like and a signup link.
This announcement feels like a "well, we're not close to shipping and we don't know if we have the resources to continue, so let's issue a press release and see if we can muster some interest to gauge if we should keep funding this". Or else it's just an announcement to help show that Google is invested in AI.
It is weird they would announce it without any real screenshots or demos. This is usable by Googlers. So it does exist, but I'll leave it to the team to hopefully actually demo it at some point.
EDIT: to add, the blog post does mention this: it is built on-top of VSCode, so it's a UI people are used to.