$ git clone -n https://src.fedoraproject.org/rpms/b43-tools.git /var/lib/mock/f41-build-841675-161335/root/chroot_tmpdir/scmroot/b43-tools
Cloning into '/var/lib/mock/f41-build-841675-161335/root/chroot_tmpdir/scmroot/b43-tools'...
$ git fetch origin 192c499a60d25c093a2c259219ba3c0694e0422b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/b43-tools
 * [new ref]         192c499a60d25c093a2c259219ba3c0694e0422b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 192c499 Spec-file cleanup