A couple other people have shared your concern. This is a fairly common practice in the world of opensource software, and services like github (where we and the original XKit Guy host our source code) allow you to edit other people’s software easily by “forking” it into your own directory. If you look at the github page, you’ll see that there are 72 forks of XKit, meaning 72 people have created their own offshoot version. XKit Guy uploaded his sourcecode to github with the intent of letting people do this.

Additionally, XKit is GPL-licensed, which grants users/other developers the right to share, copy, and modify the software. XKit Guy would have released his software under a more restrictive license if he were uncomfortable with this.

I hope this assuages your concerns!