$ git clone -n https://src.fedoraproject.org/rpms/copr-frontend.git /var/lib/mock/f41-build-side-1-2929843-35114/root/chroot_tmpdir/scmroot/copr-frontend
Cloning into '/var/lib/mock/f41-build-side-1-2929843-35114/root/chroot_tmpdir/scmroot/copr-frontend'...
$ git fetch origin bc2211cfd828bcf2cd9a55a0013f70076ed865c1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/copr-frontend
 * [new ref]         bc2211cfd828bcf2cd9a55a0013f70076ed865c1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bc2211c Update copr-frontend to 2.1-1