$ git clone -n https://src.fedoraproject.org/rpms/flmsg.git /var/lib/mock/f39-build-1532312-36223/root/chroot_tmpdir/scmroot/flmsg
Cloning into '/var/lib/mock/f39-build-1532312-36223/root/chroot_tmpdir/scmroot/flmsg'...
$ git fetch origin 2efafd26e54e1d44ecbfe18bcd2e40deee097152:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/flmsg
 * [new ref]         2efafd26e54e1d44ecbfe18bcd2e40deee097152 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2efafd2 Update to 4.0.23.