UR identified as Netscape 4.0

[TMF]

Using Firefox 2 & Ur add-on.
After copying webpage to UR, the resulting page had this note on the top:
"You are currently using Netscape 4.0. For the best experience using Yahoo!, we recommend that you upgrade to the latest version of Netscape. Get the latest version now."

This wasn't visible nor in the source code of that same page as viewed in Firefox.

This is not a problem, I'm just hoping it will not result in some problem in the future (eg. page not being served to UR due to Netscape 4.0 not being supported by the server despite it's visible fine in FF2.0).