$ git clone -n https://src.fedoraproject.org/rpms/fex-emu.git /var/lib/mock/f41-build-856589-167686/root/chroot_tmpdir/scmroot/fex-emu
Cloning into '/var/lib/mock/f41-build-856589-167686/root/chroot_tmpdir/scmroot/fex-emu'...
$ git fetch origin eb6653a15d9f3447c1ffa8f3ca0beb6209011ed1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fex-emu
 * [new ref]         eb6653a15d9f3447c1ffa8f3ca0beb6209011ed1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eb6653a Backport upstream compat input commit