Windows Longhorn/6.0.4044.Lab06 n.030915-1925

Screenshots of 6.0.4044.Lab06_n.030915-1925 were shown at PDC 2003 during Avalon Graphics and Media (Part 2). A few more screenshots were leaked afterwards which show more of this build.

PDC 2003
During PDC 2003 the screenshot was shown at the Avalon Graphics and Media (Part 2): Using Graphics, Animation and Composition in Your Applications session. They showed off how you could use their new technologies (Avalon is one of them) in your application.

Leaked screenshots
Some more screenshots were leaked later. They showed the winver dialog, explorer windows, the clock and Internet Explorer. You can also tell that this build was compiled by Lab06. Lab06 is the part where the desktop/UI gets created.