$ git clone -n https://src.fedoraproject.org/rpms/american-fuzzy-lop.git /var/lib/mock/f41-build-1290431-23344/root/chroot_tmpdir/scmroot/american-fuzzy-lop
Cloning into '/var/lib/mock/f41-build-1290431-23344/root/chroot_tmpdir/scmroot/american-fuzzy-lop'...
$ git fetch origin 0b6b53a679e673768c3180a1a78813c7a4538a7e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/american-fuzzy-lop
 * [new ref]         0b6b53a679e673768c3180a1a78813c7a4538a7e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0b6b53a New version 4.21c (RHBZ#2291250)