Facedown Cards
From Archon Arcana - The KeyForge Wiki
Some card abilities can result in cards that are facedown while in play. You may look at the reverse side of a facedown card that is in play and that you control. You may also look at the reverse side of a card that is placed facedown under a card you control. You cannot look at the reverse sides of cards you do not control.
—KeyForge Master Rulebook v17.3 March 2024