Can anyone tell me what this pipe is?

[Flexiblemouse]

Airtight guys, can anyone tell me what this is/does? it's unplugged in the picture, the o ring inside is perished and it doesn't sit well when plugged in. Potential boost leak?

 

[Flexiblemouse]

Sorry problem uploading picture

 

[desertstorm]

Looks like a crankcase ventilation pipe if it's out the top of the rocker cover.

 

[Flexiblemouse]

Ah, so not pressurised anyway then