$ git clone -n https://src.fedoraproject.org/rpms/msgpack.git /var/lib/mock/f39-build-1511681-35546/root/chroot_tmpdir/scmroot/msgpack
Cloning into '/var/lib/mock/f39-build-1511681-35546/root/chroot_tmpdir/scmroot/msgpack'...
$ git fetch origin acdbc9c98d5bc4265a803514b26b7235ab874ee8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/msgpack
 * [new ref]         acdbc9c98d5bc4265a803514b26b7235ab874ee8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at acdbc9c Upgrade from C++11 to C++14 for gtest 1.13.0