Once upon a time, there was a Macintosh. It didn't know how to handle files from the Internet, being wet behind the ears and only running System 7. Some nice Australians, who may have been involved in writing FTP clients at times, wrote a handy utility called Internet Config. It was so good that Apple included it with Mac OS 8, and by Mac OS 9 it was integrated into a nice control panel.
Around the same time, the only serious browser for the Mac was Internet Explorer. IE needed to access configuration information about, well, the Internet, so it also used Internet Config, yet, oddly, it provided its own UI for it within its preferences. (So did Netscape, to some extent, but that's not as important.)
By 2001, Apple started their move to Mac OS X, and IE came along for the ride, where the old Netscape 4 codebase didn't. Some of the functions in IC were still available through Carbon, but others weren't, and lots of the settings were no longer available in the Internet pane in Systems Preferences, which was rapidly turning into a tool to shill .mac, rather than to configure file mappings. (Anyway, file mappings were much deeper voodoo anyway, what with the deprecation of creator types.)
So where do we find ourselves with Panther? The last vestiges of Internet Config- as a preference management utility- have vanished. The System Preferences app doesn't give you a way to choose the default email or web handler; you have to do that from Apple's Mail and Safari. There's no way to control file mappings, or how to handle protocols other than http(s) and mailto. Well, no Apple-provided way. Thankfully, there's More Internet, which allows you to modify helpers (such as stopping the Finder from handling FTP; always a good idea, if you ask me). (From a poke round its nibs, it looks like it may come to allow you to configure file mappings too. That's for later, though.) Of course, if you can still stomach running IE, that'll also edit some of these preferences.
What's the moral of this story? I'm not entirely sure. There's certainly a nice feeling of circularity, though; the missing features in one OS being, nearly ten years later, hidden, waiting for a developer to come and shine a light on them.