$ git clone -n https://src.fedoraproject.org/rpms/shim.git /var/lib/mock/f38-build-side-42-init-devel-883105-28486/root/chroot_tmpdir/scmroot/shim
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-883105-28486/root/chroot_tmpdir/scmroot/shim'...
$ git fetch origin e9a64acb97e5d371f736085c662fce58aad9eb4f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/shim
 * [new ref]         e9a64acb97e5d371f736085c662fce58aad9eb4f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e9a64ac Fix aa64 unsigned rpm version