Historical Rules · 8 November 2024
Rule 103.2b
Official source text from the 8 November 2024 Rules release
If any players wish to reveal a card with a companion ability that they own from outside the game, they may do so. A player may reveal no more than one card this way, and they may do so only if their deck fulfills the condition of that card’s companion ability. The revealed card remains outside the game. (See rule 702.139, “Companion.”)