PmWiki Export works by using a Node script to communicate with a PmWiki cookbook recipe. The cookbook recipe exports PmWiki page history as a JSON object. The Node script retrieves the complete history for all pages, stores the history in a SQLite database, and "replays" each version chronologically in a new Git repository.
First add cookbook/export.php to Pmwiki's cookbook/ directory. Then add the following to local.php:
include_once('cookbook/export.php');
Next, clone the repository locally and install dependencies:
npm install
Finally, in config.js, specify what server to use and where to store the exported data. I recommend copying wiki.d/ to a clean installation of PmWiki and running locally.
Run:
node index.js
If you're like me and you have some other Git-based repo that you have been using, you can merge two repos into a single, chronologically ordered repo by following these steps on Stack Overflow.