$ git clone -n https://src.fedoraproject.org/rpms/rust-prost-build0.10.git /var/lib/mock/f42-build-side-1-3506329-45996/root/chroot_tmpdir/scmroot/rust-prost-build0.10
Cloning into '/var/lib/mock/f42-build-side-1-3506329-45996/root/chroot_tmpdir/scmroot/rust-prost-build0.10'...
$ git fetch origin 0d333bf60d89f5d6c73df5c5093e598adebf7789:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-prost-build0.10
 * [new ref]         0d333bf60d89f5d6c73df5c5093e598adebf7789 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0d333bf compat package no longer needed