$ git clone -n https://src.fedoraproject.org/rpms/Singular.git /var/lib/mock/f41-build-850714-165588/root/chroot_tmpdir/scmroot/Singular
Cloning into '/var/lib/mock/f41-build-850714-165588/root/chroot_tmpdir/scmroot/Singular'...
$ git fetch origin fcb0400bbd0bfe972727aeee23861f641a21e4d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/Singular
 * [new ref]         fcb0400bbd0bfe972727aeee23861f641a21e4d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fcb0400 Non-bootstrap build