It deals Kinetic damage and uses primary ammo. Praedyth’s Revenge is a Legendary 140 RPM Rapid-Fire Frame sniper rifle.
It seems likely that these Timelost weapons are actually the Adept versions of the Vault of Glass weapons.
In addition to the standard Vault of Glass weapons, Light.gg also displays a Timelost version of every weapon.
But most importantly, the Vault of Glass will add most of its original arsenal to Destiny 2, including fan-favorite weapons like Fatebringer and Vision of Confluence.