Consulting the Codex…
RS3 · Skills · Activities · Quests
The Codex keeps its readings for 400 days, so you can go back that far, to the first day it read Exile Dragon.
Every common prerequisite the site could check is met for Exile Dragon. Gear, abilities, perks and relics decide the rest. Quests need a public profile, so the quest checks are left out of the score.