Historical Rules · 1 October 2010
Rule 112.6k
Official source text from the 1 October 2010 Rules release
An ability that modifies the rules for deck construction functions before the game begins. Such an ability modifies not just the Comprehensive Rules, but also the Magic: The Gathering Tournament Rules and any other documents that set the deck construction rules for a specific Constructed format. However, such an ability can't affect the format legality of a card, including whether it's banned or restricted. The current Magic: The Gathering Tournament Rules can be found at http://www.wizards.com/Magic/TCG/Events.aspx?x=dci/doccenter/home.