Yes, all legacy topic migrated to this site have, have links back to the legacy site as the "Reference Thread ID" which are still the "canonical pages, as far as SEO goes", to preserve the history of the original site.
See for example:
From this link: Vim tips and tricks
This year, I'm very busy with commercial web dev transformation projects; but I plan to convert the legacy site to a Rails / Bootstrap / jQuery site, maintaining the original MySQL DB but with with Rails instead of PHP, when I have time. I don't think I will have time for that conversion in 2021.
FWIW: The legacy site also has links to the corresponding topics there that point each legacy topic to this new forum / format.
Hope this helps you understand, @hashkeeper