Throne and Liberty Encounter with Henderson Harmon
Chapter 6: The Song of the Vienta Dwarves Exploration Codex Entry

Henderson recorded his adventures in the form of songs a long time ago. If he ever knew anything about the Golem's Heart, there would be clues in his lyrics. The problem is, he took a bad hit to the head in the past and he said he doesn't remember the lyrics anymore because of it. However, it's possible Cavane, a long-time fan of his, might know.