$ git clone -n https://src.fedoraproject.org/rpms/rust-arbitrary0.4.git /var/lib/mock/f40-build-2639657-66376/root/chroot_tmpdir/scmroot/rust-arbitrary0.4
Cloning into '/var/lib/mock/f40-build-2639657-66376/root/chroot_tmpdir/scmroot/rust-arbitrary0.4'...
$ git fetch origin c87efb96e7751c2d71785a67f5f6fe4626cdb0d9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-arbitrary0.4
 * [new ref]         c87efb96e7751c2d71785a67f5f6fe4626cdb0d9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c87efb9 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild