History of Vex Portal

In Shadowkeep, Ikora Rey said that Vex Chassis Components were being used to build a Vex portal behind her, and construction began with the latest weekly reset. The components were a common-rarity drop from Vex whose only known use was Ikora's weekly "An Arm and a Leg" challenge, which rewards Powerful Gear. The source does not say what the portal does once finished.