$ git clone -n https://src.fedoraproject.org/rpms/rust-kstring.git /var/lib/mock/f45-build-42799-796/root/chroot_tmpdir/scmroot/rust-kstring
Cloning into '/var/lib/mock/f45-build-42799-796/root/chroot_tmpdir/scmroot/rust-kstring'...
$ git fetch origin 68df0b0f3546918f4a6edbe857a1244395a9fea4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-kstring
 * [new ref]         68df0b0f3546918f4a6edbe857a1244395a9fea4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 68df0b0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild