$ git clone -n https://src.fedoraproject.org/rpms/rust-pem0.8.git /var/lib/mock/f42-build-side-1-3585194-46903/root/chroot_tmpdir/scmroot/rust-pem0.8
Cloning into '/var/lib/mock/f42-build-side-1-3585194-46903/root/chroot_tmpdir/scmroot/rust-pem0.8'...
$ git fetch origin e05f1531c8409d9a1c927e4ececdc5dd8c113479:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-pem0.8
 * [new ref]         e05f1531c8409d9a1c927e4ececdc5dd8c113479 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e05f153 compat package no longer needed