It may be a specific course code or assignment ID for an educational institution (like IGNOU or similar open universities), though this is less common in public databases.
31 Mar 2025 — SONE-012 Hikaru Nagi Check Comment. Japan Television's post. Japan Television. Mar 31, 2025 Facebook·Japan Television Mun Saki Sone Session 4 Teaser Reveal - TikTok SONE-012