This is a maintenance version for the PBer's that still don't have PBWIN 10 or PBCC 6 and for the ones that have to compile existing code with PBWIN 9 or PBCC 5.
These headers are freeware, not public domain. This means that you can use them for your own purposes, even in commercial applications, without paying a fee, but not to make derivative works from, sell or redistribute without permission. Also you must assume the entire risk of using them. Downloading the software indicates that you accept these terms.