Thanks for your interest in contributing to this project!
If you want to make Icon Set Forge work with a particular icon set type of your interest, you have to implement an AbstractScannerStrategy for that icon set type. To accomplish that you may want to have a look at the following classes: IconSet, IconClassification and Icon
It has to be noted, that this diagram is neither complete nor 100% correct. Its sole purpose is to resemble the structural relations between the most relevant core classes.