Any idea about the BlueCurve theme ? Is the theme proprietary or just the trademark Blue Curve.
No, Red Hat Linux isn't proprietary software. However the Red Hat logo and name are trademarks.
Red Hat cannot prevent you from copying, modifying and/or distributing Red Hat Linux. They CAN prevent you from calling it Red Hat and using their logo or their name to promote it.
The installer etc contains some trademarked stuff, how will they affect distribution ?
Trademark != Copyright and Trademark != means of restricting distribution and/or freedom.