To fully rebuild and identify the phased Shotgun, Osiris needs components that will return it to its original state. He believes you can find those components throughout the system.
Complete the Pyramidion strike, and collect weapon enhancers by completing Crucible matches, strikes, and Gambit matches.
"The restoration is nearly complete. This Light signature is the key to understanding what this weapon is. I'm almost there, Guardian. I just need more data." —Osiris
Legendary Quest Step
2019.12.10 (Season of Dawn)