Dragontrax.co.za

A book published in 2012 called Riding the Dragon's Spine: Beit Bridge to Cape Town by David Bristow and Steve Thomas linked to this website.

"The route maps in this guidebook are supplemented by GPS tracks, which are available as free downloads from www.dragontrax.co.za" - The book

Unfortunately the website had been lost probably due to expiration of the domain.
To assist those that want to get the GPS file - a GPX file with reduced points was found at https://bikepacking.com/routes/bikepacking-south-africa-the-dragons-spine/.
Here is an alternate link: https://ridewithgps.com/routes/26649606.

Here is the GPX file from the site above: Dragon's Spine GPX File

If you have the full original file and guidebook please inform the site admin at: dragontrax@fixes.co.za