After some years, the script basically outgrew its initial intent, and moved in 2013 to its own repository.
It then continued to be updated as a stand-alone script before being properly packaged into the current form. The last known working version of the stand-alone script is available in the legacy branch.
The project lived under the name
maildir-deduplicate from 2014 to
2020. It was renamed to
mail-deduplicate in 2020 following the
mbox support alongside