What does the question about «ḥadīth al-ʿaṭṭārah» establish?

Narrator Criticism: Teacher Verification, Conflicting Ascriptions and Claims of Hearing

• Maḥmūd authenticated the complete perfumer report
• Every version under that title must have one chain
• It prompted a question to Abū Dāwūd, not authentication of that report
• It established a detailed legal rule from the perfumer narrative