So I downloaded it and it turns out it's no joke. It really is the Tor Browser Bundle for PowerPC. From the ReadMe:
The packages in this directory are UNOFFICIAL builds of the Tor Browser Bundle for Mac OS X Tiger (10.4) and Leopard (10.5), PowerPC architecture. Optimized builds are available for the different PowerPC versions, namely, the G3, G4 (7450) and G5.As said, it's a bit outdated so it's more proof of concept, but everything works. It all comes in one app bundle, and inside it are Vidalia and Firefox, with Firefox having its own profile in TorBrowser.app/Library/Application Support/, so you can run this side-by-side with TenFourFox with no problems.
The bundle is based on the official Tor Browser Bundle with changes to make it work on older Mac OS X versions and the PowerPC architecture. Most notably, Qt is downgraded to the last Mac OS X 10.4 compatible version (4.7.4) and Firefox is patched with suitable parts from the TenFourFox changeset.
Note that the 2.3.25-15 bundle version is already outdated. More current version based on Tor Browser Bundle 3.5 is in the works.
It also sets your user agent to the default Tor user agent, has private browsing enabled, and sets
network.proxy.socks_remote_dnsto "true," so all your bases are covered. It comes with two add-ons, HTTPS Everywhere and NoScript. NoScript is set to allow scripts by default, so you want to click the "Forbid Scripts" option.
Basically all you need to do is start the application, watch Vidalia establish a connection until Firefox opens to a page announcing you're browsing anonymously. Easy like it's supposed to be.
I'm also intrigued by the account name on that Sourceforge page. It's called "OS X PowerPC Packages" with the description, "A repository providing binaries of open source packages built for OS X Tiger (10.4) and Leopard (10.5) PowerPC." So maybe there'll be more in the future.