Isn “XWin” trademarked by StarNet Communications?
No. A quick search at the United States Patent and Trademark Office for “XWin” turns up one dead record and one live record. The live record is for a logo belonging to a rock crusher manufacturer based out of Belgium. Neither trademark affects Cygwin/X, as the dead record is no longer enforceable, while the live record is in an unrelated and distinct industry; there cannot be confusion between rock crushers and computer programs.