OMG, it's 6502 code! (Or for some variant of the 6502.)
Marginally interesting, the source uses standard MOS assembler syntax, but Intel-like xxH notation for hex values, rather than $xx.
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[Edit] According to Wikipedia, actually a Sunplus SPC81A microcontroller using the 6502 instruction set, but lacking the Y register:
> The first Furby model was based around a 6502-style Sunplus SPC81A microcontroller, which had 80 KiB of ROM and 128 bytes of RAM. Its core differed from the original 6502 in the lack of the Y index register. The TSP50C04 chip from Texas Instruments, implementing the linear predictive coding codec, was used for voice synthesis.