(Apologies if this was already answered somewhere − I did not locate any deployment plan).
Is GettingStarted planned to be deployed on non-Wikipedia projects ? (Speaking form a Commons perspective)
We designed GettingStarted only with Wikipedia in mind, but it's probably useful for any wiki where the focus is on editing as the first step you want a user to do. In that regard, I don't think it will be useful for Commons, since editing a File page is probably not the first thing you want someone to do. However, we could help the Commons community design a guided tour give all new users there (Rillke already made one for the Help:Nominate for deletion page).
In terms of a general non-Wikipedia strategy: we're happy to advise people on how to potentially adapt GettingStarted for your project. But for now I won't be planning to deploy the extension to any wikis other than Wikipedia unless a community requests it. It is a possibility for projects like Wikivoyage, Wikidata, and so on though.