'Mainframe' is fairly vague as an architecture name. Which mainframe architectures are supported?
'Cygwin' is technically not an operating system, it's an environment within an operating system. This distinction may be too minor to be worth changing though.
I think the Debian community would take exception to Ubuntu being listed as part of the Debian 'family'; maybe 'Debian and Debian-derived distributions' would be a better choice.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds