History of Chattering Bone (triumph)

This triumph tracks the Pattern for the Chattering Bone pulse rifle. Completing Deepsight Resonance extractions on the weapon unlocks its Pattern (progress 0/5).

How to complete

1. Get a red-border Chattering Bone from the Last Wish raid (any encounter or hidden chest can drop it).
2. Fill its Deepsight Resonance bar by using it, then extract the Pattern progress at the Enclave-style crafting bench.
3. Repeat for 5 extractions; the Pattern then unlocks and the weapon can be crafted.

Notes

The d2.destinygamewiki page confirms the 5 extractions and the raid drop. Deltia's Gaming and light.gg also cover the weapon, but I only opened the first.