Now, was this feature announced?

Not explicitly no. It was requested by a user in a PMD thread and after i implemented it I noted that I had done so in reply. See Re: RSS Syndication

Is it going to be eventually extended to all of PM?

Umm? The feeds from RAT/NN give you the same data pretty much and they cover all submitted material so im not sure why there would need to be additional feeds. Also, the site link will be relative to the one you normally use, which in your case would appear to be .org