OM648 / CDI where does high pressure pump leak from?

[atomix8]

So I've noticed a good bit of crud accumulating around my high pressure pump. At first I thought it was collecting from a leak from the breather that I can't seem to completely fix, but this looks independent after cleaning it up.

I cleaned the top and front of the pump, but didn't see a source of the leak. Bottom is grimy as you see. Electrical connector for the small sensor was wet inside with what looked diesel (it was clear, not oil). But I really don't smell diesel anywhere. Almost looks like there's a leak between the pump and the head the way junk is built up.

Where do these usually leak? All the black grime made me think it was oil, but the clear fluid in the connector seems to say otherwise.

I've seen other threads that recommend resealing, but want to make sure I've diagnosed this correctly.