Sega Retro: "Dream Passport Premier is the final(?) version of Dream Passport."
"This version of the browser was marketed as "multi-platform", as while shipping on a GD-ROM intended for the Dreamcast, the disc can be read by Windows and Macintosh computers to install versions of Dream Passport for those systems."
Dream Passport for PC use, wild. and...why would you?
computer, please put me in the timeline where the Dreamcast platform became an additional contender among Windows/Mac/Unix
This is somewhat less weird when you consider that there were actually two different web browsers for the Dreamcast.
For reasons I have never understood, Sega of America didn't ship the same web browser as what Japan and Europe got.
We got stuck with PlanetWeb, which was an awful bit of sub-WebTV quality software that pretty much was only useful for the official Sega and ISP marketing pages it was designed for, as it was basically just a standalone version of the embedded web browsers that came on a lot of the US releases. It could barely do anything, the UI was terrible, it was missing all kinds of common features you'd expect from a browser, and it made no concessions for the limitations of a standard definition television resolution so it rendered most sites horribly if at all. It eventually got a 3.0 version that added in a lot more functionality, even primitive Java applet support ... but it was only distributed by mail, on request to the ISP, and for such a limited time that almost no one ever saw a copy. Copies of the disks now apparently run a fortune on eBay.
In Japan though, they got Dream Passport, which is actually a rebranded version of ACCESS Co.'s NetFront browser. NetFront was a proper web browser, with special features like page reflow and scrolling tricks so you could surf normal web pages on a TV without them breaking. It had persistent storage so you could do things like save bookmarks and cookies even worked, and the later versions even got some very early JavaScript/CSS support IIRC. It was capable enough that it was actually my main web surfing device for a couple years in the early 2000s. You might've even heard of NetFront even if you never messed with the Japanese web browser, as ACCESS would go on to license it to Sony and Nintendo for their own consoles later on. The PSP, PS3, and 3DS all use NetFront.
Fortunately for us Americans, Sega wasn't very consistent with which of the two they embedded with game releases, so the NetFront browser slipped overseas in a few versions. Sometimes these were locked such as to block them from loading other pages than those intended, but some versions could be circumvented. Copies of ChuChu Rocket in particular were highly sought after, because they had the most recent version of NetFront embedded on the disc, and with a little trickery you could unlock the full feature set. This was literally the only thing I ever used my copy for.
So I'm not actually surprised they'd make a go of a desktop version. With a keyboard and mouse, NetFront was passable enough compared to Netscape at the time; the main limitation was just the resolution of a TV. And the codebase is apparently highly portable enough (the Wikipedia article lists dozens of platforms) that it was probably fairly straightforward to port.

