Every distinct wording since 2010, newest first.
April 14, 2023 · March of the Machine
By default, a resolving double-faced spell that becomes a permanent is put onto the battlefield with the same face up that was face up on the stack.
July 23, 2021 · Adventures in the Forgotten Realms
A double-faced card that is exiled face down remains hidden, using a face-down substitute card and/or opaque sleeves. See rule 714, “Substitute Cards.”