auth-tools/signup_form_timestamp/views/auth_signup_views.xml

<?xml version="1.0" encoding="UTF-8"?>
<odoo>
    <template id="signup_honeypot_timestamp" inherit_id="auth_signup.signup">
        <xpath expr="//form" position="inside">
            <input type="hidden" t-att-name="timestamp_name" t-att-value="signup_timestamp"/>
        </xpath>
    </template>
</odoo>