$ git clone -n https://src.fedoraproject.org/rpms/rust-mimalloc.git /var/lib/mock/f45-build-43255-801/root/chroot_tmpdir/scmroot/rust-mimalloc
Cloning into '/var/lib/mock/f45-build-43255-801/root/chroot_tmpdir/scmroot/rust-mimalloc'...
$ git fetch origin 68c9501dd2c01f8c053fa280a4d721ec21c019ca:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-mimalloc
 * [new ref]         68c9501dd2c01f8c053fa280a4d721ec21c019ca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 68c9501 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild