Razor Crest Title - Hidden information

[Raph]

Hey guys, question about the hidden Illicit card granted by the Razor Crest title. For reference, that card reads:

Quote

Place 1 non-limited [Illicit] upgrade facedown under this card.

During the System Phase, you may reveal that [Illicit] upgrade and equip it as if it were equipped at Setup (without paying its points cost).

Question 3: Is this facedown card known to your opponent, or is this information hidden until the card is revealed?

Edited April 18, 2022 by Kris M
Editted title for clarity

[Kris M]

The card placed under the title is hidden information until the owner decides to reveal it