$ git clone -n https://src.fedoraproject.org/rpms/rust-proc-macro-error.git /var/lib/mock/f40-build-2642936-66478/root/chroot_tmpdir/scmroot/rust-proc-macro-error
Cloning into '/var/lib/mock/f40-build-2642936-66478/root/chroot_tmpdir/scmroot/rust-proc-macro-error'...
$ git fetch origin a6fa4074fd7df5eace9f7ed77d07e68f2489d604:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-proc-macro-error
 * [new ref]         a6fa4074fd7df5eace9f7ed77d07e68f2489d604 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a6fa407 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild