Rules glossary
↑ Parent rule: 903.11 Except via rules, special actions, and effects that specific…
903.11a If a player is allowed to bring a card from outside the game into a Commander game, that player can’t bring a card into the game this way if it has the same name as a card that player had in their starting deck, if it has the same name as a card that the player owns in the current game, or if any color in its color identity isn’t in the color identity of the player’s commander.
No sub-rules.