How should desired orientation be expressed in solveIK()?

[rcywongaa]

From https://files.hebi.us/docs/cpp/cpp-3.5.1/classhebi_1_1experimental_1_1arm_1_1Arm.html#aa4eb194bc441c71efdcf7f6e20f5178e)

Eigen::VectorXd hebi::experimental::arm::Arm::solveIK(
    const Eigen::VectorXd& initial_positions,
    const Eigen::Vector3d &	target_xyz,
    const Eigen::Vector3d &	end_tip 
) const

What is the interpretation of end_tip?

If I set end_tip = [1, 1, 1], does that mean the end effector will point at [1,1,1] in world frame? Or is it a rotation of [1,1,1] along the end effector x, y, z axis?

Similarly, from https://files.hebi.us/docs/python/2.7.2/hebi/py_api.html?highlight=endeffector_so3_objective#hebi.robot_model.endeffector_so3_objective

robot_model.endeffector_so3_objective(weight: float = 1.0)

In what frame is the orientation specified in?