$ git clone -n https://src.fedoraproject.org/rpms/rust-vergen.git /var/lib/mock/f45-build-46060-830/root/chroot_tmpdir/scmroot/rust-vergen
Cloning into '/var/lib/mock/f45-build-46060-830/root/chroot_tmpdir/scmroot/rust-vergen'...
$ git fetch origin 7c63ff616aa9314dbf41eeb42459269be7bea0a4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-vergen
 * [new ref]         7c63ff616aa9314dbf41eeb42459269be7bea0a4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7c63ff6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild