$ git clone -n https://src.fedoraproject.org/rpms/rust-libmimalloc-sys.git /var/lib/mock/f45-build-42931-797/root/chroot_tmpdir/scmroot/rust-libmimalloc-sys
Cloning into '/var/lib/mock/f45-build-42931-797/root/chroot_tmpdir/scmroot/rust-libmimalloc-sys'...
$ git fetch origin 1ea235f232679459fcf7977ced9139636a6a7324:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-libmimalloc-sys
 * [new ref]         1ea235f232679459fcf7977ced9139636a6a7324 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1ea235f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild