The Tormach github is here: Tormach Inc. · GitHub
You also have full access to the source code running on your controller. Some folks go in and make modifications, though keep in mind that is a “you are on your own” kind of thing. You will want some form of version control as well to track any changes you make as new updates will wipe out customizations.
Here are a couple related forums posts that might be useful to you as well as examples:
Guidance on installing additional packages - PathPilot - Tormach Forums
A-Axis Scaling - PathPilot - Tormach Forums