$ git clone -n https://src.fedoraproject.org/rpms/foomuuri.git /var/lib/mock/f38-build-side-42-init-devel-1407218-31287/root/chroot_tmpdir/scmroot/foomuuri
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1407218-31287/root/chroot_tmpdir/scmroot/foomuuri'...
$ git fetch origin 5f310a517a7d2667f22b9463612330b5c0e1ca96:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/foomuuri
 * [new ref]         5f310a517a7d2667f22b9463612330b5c0e1ca96 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f310a5 0.21