Opera is the first non-Safari browser and BitTorrent client in the Mac App Store
Its description in the store is fairly tame, trumpeting Opera's speed and security along with gesture support and its trademark speed dial page. There's no mention of extension support or the built-in email client, though both are shown in the screenshots.
Something else which isn't called out is the fact that Opera can also download torrents -- and that's not something Apple has ever looked too kindly upon. Opera's BitTorrent support is rarely discussed, and it isn't depicted in the App Store description or images, either. Still, with built-in support for a technology that Apple has historically linked to illegal use, it will be interesting to see just how long Opera is welcome to stay at Apple's party.