From Guild Wars 2 Wiki
Double-click to reveal the true nature of a nearby raven.
— In-game description
- Likely a reference to The Amber Spyglass book by Philip Pullman. The icon is very similar to the book cover of The Amber Spyglass, the recipe contains Ambrite (Amber), and "Subtle" is used in the title of the previous book in the series, The Subtle Knife.