How name="%(window_action)d" in button works in Odoo?

Specifically, I try to understand how 'Configure Variant' in product template view works. In product_views.xml in product module it got:

<button string="Configure Variants" type="action"
   name="%(product_attribute_value_action)d"
   attrs="{'invisible': ['|', ('attribute_line_ids', '&lt;=', 0), ('is_product_variant', '=', True)]}"
groups="product.group_product_variant"/>

How does Odoo recognize product_attribute_value_action to deliver correct ir.act_window action? I try to find product_attribute_value_action declaration anywhere but cant find it.

Using the name of your button ("product_attribute_value_action"), you can define your action this way, so that it will open the existing product-attributes's view: product_attribute_view_form

<button string="Configure Variants" type="action"
   name="%(product_attribute_value_action)d" />

<record id="product_attribute_value_action" model="ir.actions.act_window">
        <field name="name">Product Attributes</field>
        <field name="type">ir.actions.act_window</field>
        <field name="res_model">product.attribute</field>
        <field name="view_mode">form</field>
        <field name="target">new</field>
        <field name="view_id" ref="product_attribute_view_form"/>
</record>

ALREADY EXISTING VIEW FORM (in /addons/product/view/product_attributes_views.xml):

    <record id="product_attribute_view_form" model="ir.ui.view">
        <field name="name">product.attribute.form</field>
        <field name="model">product.attribute</field>
        <field name="arch" type="xml">
            <form string="Product Attribute">
            <field name="number_related_products" invisible="1"/>
            <sheet>
                <div class="oe_button_box" name="button_box">
                    <button class="oe_stat_button" name="action_open_related_products"
                            type="object" icon="fa-bars"
                            attrs="{'invisible': [('number_related_products', '=', [])]}">
                        <div class="o_stat_info">
                            <span class="o_stat_value"><field name="number_related_products"/></span>
                            <span class="o_stat_text">Related Products</span>
                        </div>
                    </button>
                </div>
                <group name="main_fields" class="o_label_nowrap">
                    <label for="name" string="Attribute Name"/>
                    <field name="name" nolabel="1"/>
                    <field name="display_type" widget="radio"/>
                    <field name="create_variant" widget="radio" attrs="{'readonly': [('number_related_products', '!=', 0)]}"/>
                </group>
                <notebook>
                    <page string="Attribute Values" name="attribute_values">
                        <field name="value_ids" widget="one2many" nolabel="1">
                            <tree string="Values" editable="bottom">
                                <field name="sequence" widget="handle"/>
                                <field name="name"/>
                                <field name="display_type" invisible="1"/>
                                <field name="is_custom" groups="product.group_product_variant"/>
                                <field name="html_color" attrs="{'column_invisible': [('parent.display_type', '!=', 'color')]}" widget="color"/>
                            </tree>
                        </field>
                    </page>
                </notebook>
            </sheet>
            </form>
        </field>
    </record>