$ git clone -n https://src.fedoraproject.org/rpms/loupe.git /var/lib/mock/f39-build-1895842-42814/root/chroot_tmpdir/scmroot/loupe
Cloning into '/var/lib/mock/f39-build-1895842-42814/root/chroot_tmpdir/scmroot/loupe'...
$ git fetch origin 5fa9955e5362e17ce1542e60384167d08a9524e3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/loupe
 * [new ref]         5fa9955e5362e17ce1542e60384167d08a9524e3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5fa9955 Update to 45.2