$ git clone -n https://src.fedoraproject.org/rpms/rust-rustcat.git /var/lib/mock/f45-build-44564-815/root/chroot_tmpdir/scmroot/rust-rustcat
Cloning into '/var/lib/mock/f45-build-44564-815/root/chroot_tmpdir/scmroot/rust-rustcat'...
$ git fetch origin b4f26dcf3c713fe92454c0edba49c9ca5efe3d86:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rustcat
 * [new ref]         b4f26dcf3c713fe92454c0edba49c9ca5efe3d86 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b4f26dc Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild