$ git clone -n https://src.fedoraproject.org/rpms/rust-quick-xml0.31.git /var/lib/mock/f45-build-44190-811/root/chroot_tmpdir/scmroot/rust-quick-xml0.31
Cloning into '/var/lib/mock/f45-build-44190-811/root/chroot_tmpdir/scmroot/rust-quick-xml0.31'...
$ git fetch origin b47d5c205ad9fba1452e27c31d81f2e7921f55ab:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-quick-xml0.31
 * [new ref]         b47d5c205ad9fba1452e27c31d81f2e7921f55ab -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b47d5c2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild