In order for an add-on to appear on community add-ons website, it must go through a queue process involving pull requests to a specific GitHub repository, typically initiated by an add-on author or people who have received permission from the author to post a pull request on their behalf.
If it is the add-on I'm thinking of, then suffice to say that it may need some internal adjustments (some of them major). I believe there has been requests to register that add-on on community add-ons website for some time and we had discussions about it, specifically add-on scope as the add-on covers a lot.
As for ClipSpeak, yes, the author is one and the same (Damien). The add-ons community had a discussion about what to do with this add-on a while back with no solid conclusions. My hope is that someone would maintain that add-on and make it compatible with newer NVDA releases (I wish I could, but I'm at a point where I cannot guarantee it).