Seen on Reddit and on eBay, two prototypes of the first PowerBook G3, derived from the PowerBook 3400c.
At the time, when Apple integrated a new processor designed for Mac OS, it did something similar to what it does now: keeping the same machine with a new CPU. But the PowerBook G3 Kanga is unfortunately a rather average machine (unlike the M1) that was not supported under Mac OS X.
The one on Reddit, notably, has Intel flash memory chips for the ROM (I suppose).
The second one on eBay is in worse condition.