From Princess Zelda

"" is an ST: in. As its name suggests, it is a ST: from ST:.

Location and Uses
After swearing him in as a ST:, ST: secretly hands ST: the ST: at the end of the ceremony. It contains a ST: with directions for reaching her quarters via a secret path at the top of ST:. The ST: reads,

Trivia

 * As the ST: is obtained during a cutscene, ST: does not it hold up like he does with other NaN Items.