$ git clone -n https://src.fedoraproject.org/rpms/rust-prost0.10.git /var/lib/mock/f42-build-side-1-3586527-46923/root/chroot_tmpdir/scmroot/rust-prost0.10
Cloning into '/var/lib/mock/f42-build-side-1-3586527-46923/root/chroot_tmpdir/scmroot/rust-prost0.10'...
$ git fetch origin e1a9210f30ee4acaf5eb5e06d1d1e0b6e837258e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-prost0.10
 * [new ref]         e1a9210f30ee4acaf5eb5e06d1d1e0b6e837258e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e1a9210 compat package no longer needed