The same label is slapped on core Windows CE 5.0 devices, only with "5.0" in place of "6.0." Microsoft gives a rough explanation here:
http://www.microsoft.com/windowsembedded/en-us/products/windowsce/component-library.mspx
It appears that the label refers to the core OS plus Internet Explorer CE 6.0, ActiveSync files, Remote Desktop, Windows Media Player 9 for Windows CE, and the ClearVue reader suite
(Word Viewer, Excel Viewer, PowerPoint Viewer, PDF Viewer, and Image Viewer
).