Due to their article editing policies, Wikimedia sites like Wikipedia have become inadvertent time capsules for IPv6 addresses. When Wikimedia users make edits without signing into an account, their IP addresses are used in lieu of a username. Wikimedia site dumps therefore provide researchers with over two decades worth of timestamped client IPv6 addresses to understand address assignments and how they have changed over time and space. In this work, we extract 19M unique IPv6 addresses from Wikimedia sites like Wikipedia that were used by editors from 2003 to 2024. We use these addresses to understand the prevalence of IPv6 in countries corresponding to Wikimedia site languages, how IPv6 adoption has grown over time, and the prevalence of EUI-64 addressing on client devices like desktops, laptops, and mobile phones.