$ git clone -n https://src.fedoraproject.org/rpms/rust-arbitrary.git /var/lib/mock/f40-build-2639654-66376/root/chroot_tmpdir/scmroot/rust-arbitrary
Cloning into '/var/lib/mock/f40-build-2639654-66376/root/chroot_tmpdir/scmroot/rust-arbitrary'...
$ git fetch origin e040d1612174c5bb7db759e4a900ecc2468f1d22:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-arbitrary
 * [new ref]         e040d1612174c5bb7db759e4a900ecc2468f1d22 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e040d16 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild