Funky diff in my XX4???

[RC944]

so finally getting around to rebuilding my XX4 WE and noticed this rather strange 'diff' at the front

no ballraces, thrus washers etc. the blue parts are married to the white pulley by screws and are fixed. 2 ballraces sit in the chassis and inside are the blue parts. the outdrives are then place in the blue parts but can only rotate one way. the dogbone is located in the outdrive with a coil spring in between. 2 questions

- what the hell is this thing
- is it better or worse than the conventional diff with plastic outdrives

thanks!