The Pro Tour is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Draft—When you planeswalk here, each player opens a booster pack, drafts a card, and exiles it face down. Each player may play the card they drafted for as long as it remains exiled. Players may spend any type of mana to cast spells this way. Standard—Whenever chaos ensues, each player draws cards equal to the number of differently named Standard-legal cards they control. (Basic lands count. Tokens don't.)