How papers are selected for Best Paper, Oral, or Highlight presentation at major ML/CV conferences such as CVPR, ICCV, ECCV, NeurIPS, and ICLR? [D]

From what I understand, reviewers usually do not directly vote for these categories or nominate papers themselves. So how does the selection process typically work? Here are specific questions I wonder - Who actually selects the candidates: ACs, SACs, program chairs, award committees, or a separate