Thanks a lot for your positive feedback!
Are you referring to altering the source code for the Editor GUI, or referring to creating some custom condition which you want to be assigned on the transitions?
If you want to alter the code so that all transitions/connections already come with a condition assigned, then probably the best way to do this, would be to open up the FSMConnection.cs and add these lines of code in the class, replacing the condition type with the type you want: