To find all Prims with a certain Attribute, you can Traverse the stage and use Usd.Object.IsValid() combined with Usd.Prim.GetAttribute() to check if the Attribute you are looking for exists for each prim in the stage.
To find all Prims with a certain Attribute, you can Traverse the stage and use Usd.Object.IsValid() combined with Usd.Prim.GetAttribute() to check if the Attribute you are looking for exists for each prim in the stage.