From Archon Arcana - The KeyForge Wiki

When a player searches a game area (such as a deck), that player looks at all the cards in the specified area without showing those cards to the opponent. A player may choose to fail to find the object of a search. If an entire deck is searched, the deck must be adequately shuffled upon completion of the search.

If a discard pile is searched, the cards are kept in the same order.

Official rules v1.7 December 2020