It is interesting how the closed source issue is consistently raised on HN with respect to k when there are numerous other examples of closed source software used by HN readers where I never see this issue raised. In those cases it does not seem to be important. For some reason however, it seems availablity of source code is important to some folks in the case of k.
I am curious; What would you do with the source code? Is it an issue of verifying what the software is doing, or perhaps being able to modify the software or make "fixes"? Is it something else? Maybe you simply want a free option for commercial use. If the later, please disregard my curiosity.
For me the issue I have with k being closed source has always been ports, i.e., limited OS support. They used to have a FreeBSD port many years ago, but today there is no support for OS other than Windows/Solaris/Linux, e.g., NetBSD.