This very unknown cpu, was used in laptop PC. But actullay, only the cpu die assembly
in package was done by Mitsubishi.
The cpu die itself, was delivered directly by Intel, in what they call "GEL-PAK".
These dies directly delivered to OEMs were called SmartDIE™ by Intel.
It is sure that many other manufacturers used these dies for their chips, using their proprietary cpu package, according to their needs. Knowing that they are using Intel's dies, without dissambling the laptops, it is impossible to find out what is really the cpu (it will show as an Intel Pentium in BIOS for example).
Maybe even also the Fujitsu Pentium are manufactured using this Intel's SmartDIE, but until now, it has not been proved.