Grey shirts noroot firewall: Trustful?

Hi all,
a central security feature like a firewall should be absolutely trustful. What about noroot firewall? I was searching some information about the author, I was looking for any hints about the source code - nothing! Just 1000 places where it can be downloaded. I like the app because of it’s simple user interface, but I’m concerned about what it really does, despite of some reports of “not calling home” in the monitored time (see e.g. here:•-noroot-firewall)
Does anybody have some information about grey shirts noroot app? Who stands behind it? What is the business model? Is it pure altruism? If so, why isn’t it OSS? Or did I just not look on the right places?
Thanks in advance!