$ git clone -n https://src.fedoraproject.org/rpms/rust-ar.git /var/lib/mock/f45-build-40109-768/root/chroot_tmpdir/scmroot/rust-ar
Cloning into '/var/lib/mock/f45-build-40109-768/root/chroot_tmpdir/scmroot/rust-ar'...
$ git fetch origin 25e7e5ab778f0f4d1dabf3f36d827c9cf3259ba9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-ar
 * [new ref]         25e7e5ab778f0f4d1dabf3f36d827c9cf3259ba9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 25e7e5a Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild