Where do I find OIDs for the domains I see in RoseTree?

Yeah! I was a little confusing finding OID in generation of the Vocabulary.xml.
So, I wanted to post these lines where I can find those.
Refer to this link for downloading the OIDs.
http://www.hl7.org/oid/
Download the internal and external OIDs.

You can then notice the SymbolicName matching the VocSet Name from Vocabulary.xml.

Here is a useful link to find out why HL7 did that.
http://wiki.hl7.org/index.php?title=HL7_Oid_Symposium_(INM_and_VOCAB)
If anyone have information about why are OIDs separated from Vocabulary.xml, you are more than welcome to post in the comments.