This isn’t the case, at least not at the moment. Having just purchased this, I’m quite unhappy that I can not even open the config file of the multicharacter, for example. If the product is both advertised as open source in your title, on your Tebex and then claim that code is accessible, at least make that the case.
Hopefully this can be resolved soon as it seems like a fantastic resource but I won’t get much use out of it until I can actually get into the config etc. to set things up how I like them.
Update: This issue was fixed and the developer was extremely helpful in providing me with the files I needed! 5 Star Support!