Sufyan said, "I only know it as from the Prophet ﷺ." Regarding "or some remnant of knowledge" [Ahqaf 46:4], he said, "It refers to writing."
قال سفيان: لا أعلمه إلا عن النبي ﷺ- {أو أثرة من علم} قال: الخط.
Ahmad (1992) narrated it from Yahya, from Sufyan, who said, Safwan bin Salim told us, from Abu Salama bin Abdul-Rahman, from Ibn Abbas, and he related it. Its isnad is sahih.Hakim (2/454) also reported it through another route from Sufyan, with the same wording, as a stopped narration (mawquf), and he graded it sahih according to the standard of the two Shaykhs (Bukhari and Muslim).