$ git clone -n https://src.fedoraproject.org/rpms/python-boto3.git /var/lib/mock/f42-build-side-111012-59199750-6571809/root/chroot_tmpdir/scmroot/python-boto3
Cloning into '/var/lib/mock/f42-build-side-111012-59199750-6571809/root/chroot_tmpdir/scmroot/python-boto3'...
$ git fetch origin 059561f636d5ee6b7c2cd7a84035bfb783200d4d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-boto3
 * [new ref]         059561f636d5ee6b7c2cd7a84035bfb783200d4d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 059561f 1.38.5