First we'll deploy the extension to MediaWiki.org and test2.wikipedia.org. These will be good places to stage our first features and make sure everything is in good shape before continuing to deploy to the next batch of places.
We'll also solicit simple features that other teams, or volunteers, want to deploy in this manner.
Second batch of wikis
Next, we'll deploy to French Wikipedia, which community has expressed interest in having some of the Multimedia team's experimental features. This consensus conversation, to my knowledge, has not begun yet. Should be deployed in conjunction with Extension:MultimediaViewer.