manufacture/mrp_bom_tracking/views/bom_template.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2019 Eficent Business and IT Consulting Services S.L.
     License LGPL-3.0 or later (https://www.gnu.org/licenses/lgpl). -->

<odoo>
    <template id="track_bom_line_template">
        <div>
            <strong>The component quantities or UoMs have been updated.</strong>
            <ul>
                <t t-foreach="lines" t-as="line">
                    <li><t t-esc="line.product_id.display_name"/>:</li>
                    Product Quantity: <t t-esc="line.product_qty" /><t t-if='line.product_qty != product_qty'> -&gt; <t t-esc="float(product_qty)"/></t><br/>
                    Product Unit of Measure: <t t-esc="line.product_uom_id.display_name" /><t t-if='line.product_uom_id != product_uom_id'> -&gt; <t t-esc="product_uom_id.display_name"/></t><br/>
                </t>
            </ul>
        </div>
    </template>

    <template id="track_bom_template">
        <div>
            <strong>The components have changed.</strong>
            <ul>
                <t t-foreach="lines" t-as="line">
                <li><t t-esc="line.product_id.display_name"/>:
                <t t-esc="mode"/> component<br/></li>
                </t>
            </ul>
        </div>
    </template>

    <template id="track_bom_template_2">
        <div>
            <strong>The components have changed.</strong>
            <ul>
                <t t-foreach="lines" t-as="line">
                <li><t t-esc="line.product_id.display_name"/>:
                Removed component<br/></li>
                <li><t t-esc="product_id.display_name"/>:
                New component<br/></li>
                </t>
            </ul>
        </div>
    </template>
</odoo>