Blueprint for the Harrow Warframe is awarded by completing the Chains of Harrow quest. Component blueprints are hidden in the Kuva Fortress, Defection missions and dropped from Corrupted Void Fissure enemies.

Item	Count	Source
Harrow Neuroptics	1	Kuva Fortress/Pago (Spy), C 11.28%
Harrow Chassis	1	Void Fissure Corrupted Enemy 3.00%
Harrow Systems	1	Neptune/Yursa (Defection), C 11.28% Saturn/Caracol (Defection), C 11.28% Phobos/Memphis (Defection), C 7.52% Neptune/Yursa (Defection), B 2.01% Phobos/Memphis (Defection), B 2.01% 1 more…
Kuva	2,000