Hi,

In Odoo %(product_attribute_value_action)d is a special syntax used by Odoo to reference the XML ID of the action.

The action definition is :

<record id="product_attribute_value_action" model="ir.actions.act_window">

        <field name="name">Product Variant Values</field>

        <field name="res_model">product.template.attribute.value</field>

        <field name="view_mode">tree,form</field>

        <field name="domain">[('product_tmpl_id', '=', active_id)]</field>

        <field name="view_ids"

                eval="[(5, 0, 0),

                (0, 0, {'view_mode': 'tree', 'view_id': ref('product.product_template_attribute_value_view_tree')}),

                (0, 0, {'view_mode': 'form', 'view_id': ref('product.product_template_attribute_value_view_form')})]" />

        <field name="context">{

            'default_product_tmpl_id': active_id,

            'search_default_active': 1,

        }</field>

    </record>

Hope it helps