Citrus Red 2, Citrus Red No. 2, C.I. Solvent Red 80, or C.I. 12156 is an artificial dye. As a food dye, it has been permitted by the US Food and Drug Administration since 1956 to color the skin of oranges. From Wikipedia
FDA revocations of Citrus Red No. 2 and Orange B approvals along with new natural color certifications underscore HHS’s plan to eliminate artificial dyes by 2026.