In-Universe:
The newly christened U.S.S. Defiant (formerly Sao Paulo) waits for her orders with the rest of the combined Alpha quadrant fleet.
Production:
This looks to be the 4th CGI model used by Digital Muse which I'll call V4. I think this is the same as V3 but with a completely new skin that includes aztecing on the hull.
*This is an updated scene from the sixth season episode 'Sacrifice of Angels', with new models, textures and a few different ships.
