$ git clone -n https://src.fedoraproject.org/rpms/fedora-flathub-remote.git /var/lib/mock/f45-build-8853-396/root/chroot_tmpdir/scmroot/fedora-flathub-remote
Cloning into '/var/lib/mock/f45-build-8853-396/root/chroot_tmpdir/scmroot/fedora-flathub-remote'...
$ git fetch origin 98fa7beb02dc407358a3da8b58f7f27507370400:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-flathub-remote
 * [new ref]         98fa7beb02dc407358a3da8b58f7f27507370400 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 98fa7be Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild