The W3C HTML standard allows browsers to wrap text to fit a window. Both MSIE and Netscape wrap by default. To avoid wrapping, a web author can add a "nowrap" tag to an element. This tag is in the standard - it is neither a Netscape nor a Microsoft extension.
There are a great many unspecified areas of HTML. When the W3C standard does not dictate how a particular type of code is to be handled then a browser may handle that markup language as its developers see fit. For example, suppose that a table entry is tagged with both "nowrap" and a specified "width". What happens if the specified width is less than the unwrapped text that appears in that table entry? The web author is telling the browser to perform incompatible tasks. Should the browser respect the width specification or should it respect the nowrap directive? It seems to me that the standard does not answer this question. If so, then the browser developer is free to make the determination.
That seems to me to be what is going on with the new PPRUNE HTML markup. Some table entries have both widths and nowraps. It appears that MSIE is letting the width specification take precedence over the nowrap and that Netscape is allowing the nowrap to take precedence over the width specification.
I don't really see why the "nowrap" tag has been included anyway.