Treachery is a subformat of EDH which incorporates hidden roles to spice up the game and increase the prevalence of political play.
The rules of Treachery and the additional materials can be found here: https://mtgtreachery.net/en/#howto
This cube has the additional following rules:
4 x 20 card packs, pick 2, for 60-card decks.
All mono and dual colored commanders have Partner, so long as the total number of colors in your command zone does not exceed 3. This does not stack with Choose a Background or Doctor's Companion -- You may only have two commanders total.
Each player may add a Command Tower to their deck during deck construction.
Any number of players may pay any number of generic mana for Assist cards, rather than just 1.