Yes it is true. Some of the original people that worked on the Mac GUI became part of a company (Eazel) and made a file browser called Nautilus.
For more info see:
http://www.eazel.com
Nautilus has some very cool features and looks very nice. It has "photorealistic" resizeable icons, "play-on-hover" for MP3 files, thumbnail icons for graphics AND plain text files, different skins,... in short... all sorts of GUI candy.
And yes it runs on LinuxPPC.
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