Zelda Universe, a game registered by Nintendo, has appeared on the Entertainment Software Rating Board’s website and is listed as a game for the “online” platform.

The rest of Nintendo’s games are listed for specific platforms like the Nintendo DS and Wii — the company’s most popular consoles. The game doesn’t seem to be an online role-playing game like World of Warcraft, because those games are listed as games for the Macintosh and PC. Some online games like EVE Online are cross-linked as Macintosh, PC and online games. Flash games like Sorry! and Scrabble are listed as exclusively online games.

If Nintendo is applying for a rating for the game, that means it is nearly complete. It could be a working title for Nintendo’s 3D remake of The Legend of Zelda: Ocarina of Time, which is due for the Nintendo 3DS next month. But the title is not labeled as a Nintendo 3DS title, which other titles such as Cave Story 3D appear under on the ESRB’s website. The title could also be related to a massively multiplayer online game for the company’s next console, the Wii 2 — which should be announced and available at the Electronic Entertainment Expo (E3) conference in Los Angeles, Calif., next month.

Nintendo announced The Legend of Zelda: Skyward Sword at E3 last year, and it is due for release sometime this year, about five years after the debut of the last Zelda title for the console. That title has not appeared on the ESRB’s website. Nintendo could also be poised to make an announcement about the game at E3, which is now just about two weeks away. Nintendo’s press conference takes place June 7.

Another hint about the game could come from its name: “Universe.” Nintendo could be creating an online experience similar to other games that crosses multiple platforms — such as the iPhone, the Nintendo DS and the company’s consoles. Skyward Sword could be at the heart of that experience, with other interactive elements like alternate reality games, flash games and mobile apps also feeding in. “Zelda Universe” is also the name of the main website that serves as a hub for all of Nintendo’s Zelda games.

We’ve contacted Nintendo to find out about the game and will update the story as more information comes in.