meta-openembedded was not forked. The reason we removed the .git info from there is to save space in that (humongous) tarball.
If you’re working with Yocto 1.7, the meta-oe revision is likely 70beecb.
If you’re working with Yocto 2.2, meta-oe is likely fe5c8331.
That tarball is a ‘less than optimal’ way to distribute this stuff, and we’re actively working for a way to distribute the distribution as native git for early 2018.