In what has become an unfortunate tradition for the past few releases, prior to the release of Ubuntu 10.10, AMD provided Canonical with a pre-release of their latest proprietary Catalyst driver at the time. They have done this to fix some major bugs, but primarily to provide a working ATI/AMD proprietary graphics driver that will run against their latest Ubuntu Linux release as usually their latest public releases at the time do not support Ubuntu's kernel and/or X.Org Server. With Maverick Meerkat, which was released yesterday, there is a pre-release of the Catalyst 10.10 Linux driver, which will not be released to the general public until later in October.
The Catalyst 10.9 driver does not offer support for X.Org Server 1.9, which is used by Ubuntu 10.10, so in late September AMD had sent over an early Catalyst 10.10 driver to Canonical that offers "early look" support for this xorg-server that reached a stable status in August. Those running Ubuntu 10.10 and enabling the proprietary ATI/AMD support are using this driver.
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