What is the grammatical status of wujūhun in 88:2?

Supplementary Practice 28 — Comparative Rhetoric of Sūrat al-Aʿlā and Sūrat al-Ghāshiyah

• An indefinite subject (mubtadaʾ)
• The first object of an omitted verb
• A genitive substitute for ḥadīth
• An accusative specification