Moving files in sync? What's the strategy?

Hi, I just found out that timezone.el isn't in sync. I guess there are some other packages and files that isn't in sync either but then what is the procedure for getting a particular file in sync? I guess there could be some serious problems caused by just syncing a few files if not done properly. So one has to be carful doping it. But coding around lack of functionality in XEmacs isn't fun either so there should be some interest in getting things in sync I guess. Comments, suggestions? Yours -- %% Mats