infrastructure/roles/matrix_delegate/templates/client-delegation.json

{
    "m.homeserver": {
      "base_url": "https://{{ matrix_delegate_matrix_domain }}"
    }{% if matrix_delegate_sliding_sync_enabled %},
    "org.matrix.msc3575.proxy": {
		"url": "{{ matrix_delegate_sliding_sync_url }}"
	}
{% endif %}
}