strange pipe

just finished fitting a 200tdi engine to my classic rr, the engine i bought off ebay and was apparently taken out f a 1994 disco, i noticed when i first got the engine that there is a small nylon pipe coming from the timing belt cover, where the inspection flap to the injector pump is, its about 1 metere long and has a block with more push in connectors, i thought it might be some kind of vacuum pipe, but dont know, not seen this before, engine runs fine so just coiled it up and left it, anybody know what it is ?

Timing case breather for wading. Others for axles and boxes.

thanks, for quick reply