Odd crank case wading /drain plug arrangement?

[Serious Series]

Anyone familiar with this arrangement for plugging / draining the crank case.
Ie do they know what engine had this arrangement.

[diffwhine]

Thanks... Now my curiosity means I've got to now go and sort through my pile of flywheel housings and see if I have anything similar... 

Makes far more sense than that silly right angle bracket that just got binned at the first clutch change.