If used together as a journal entry or status update, "FU10 day watching 18 31 new" could be interpreted as:
Disclaimer: This article is for educational and informational purposes only. It does not condone, promote, or provide access to any unauthorized streaming, surveillance bypass, or age-inappropriate material. If you believe this phrase is being used to conceal illegal activity, report it to your local cybercrime unit.
Day 3 — Nomadland (2020)
In a world of infinite scrolling, the phrase asks us to slow down. To pick a specific file, a specific day, and a specific time, and simply watch. You never know what might be "new" in the old.