Seen on eBay, some CDs I had never seen before: the Release Candidate of Mac OS X.
Given the date, this is indeed the Release Candidate of Mac OS X 10.0 (the first version). A Release Candidate is a test version that is supposed to be the final release… unless a major bug is discovered. In most cases, the RC is identical to the final version but may (sometimes) have slight differences if last-minute issues arise.
Here, there are two discs: one with the operating system itself and a second with the developer tools.
