All packages listed here are free. There are no warranties of any kind, and there is no service or technical support available for these from IBM.
These tools were designed for z/OS UNIX by IBM developers and testers. Unless otherwise noted, most of the tools are not very portable. They probably will not work well on other UNIX systems without at least a little modification. The packages provided here are working to the satisfaction of the people who ported them. If you have a problem working with a package, open an issue.
If you are looking for ported open source tools for z/OS, Rocket Software provides an extensive collection.