Because of a bug in Mac OS X 10.2 the mouse cursor was sometimes displayed in wrong colors.
Downloads were passed twice to external helper applications under Mac OS X 10.2.
Under Mac OS X 10.2 the Quicktime plugin was not recognized anymore.
A bug in the finder of Mac OS X 10.2 prevents that you can move partial downloads to the trash can. To delete such files other applications must be used. Now iCab will remove the "partial" status from these files when the download is aborted so that the finder is able to delete such files again.
Scrolling horizontally using the scroll wheel is now supported under Mac OS X 10.2 (hold down the shift key to scroll horizontally).
Some other modifications for Mac OS X 10.2 (Jaguar)
Since Mac OS X 10.1.5 you can enable the Quarz text rendering in icab (in the very first preferences panel of the preferences dialog)
You can now enable a DNS cache (Preferences > Network > HTTP, DNS) to reduce the connections to the name server.