$ git clone -n https://src.fedoraproject.org/rpms/booth.git /var/lib/mock/f40-build-1991897-43533/root/chroot_tmpdir/scmroot/booth
Cloning into '/var/lib/mock/f40-build-1991897-43533/root/chroot_tmpdir/scmroot/booth'...
$ git fetch origin 3838e60516e2c4ada00e3e9df2be60b87e00dd06:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/booth
 * [new ref]         3838e60516e2c4ada00e3e9df2be60b87e00dd06 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3838e60 New upstream release