trytond-sale_line_quick_actions/view/line_split_form.xml

<?xml version="1.0"?>
<!-- The COPYRIGHT file at the top level of this repository contains the full
     copyright notices and license terms. -->
<form>
    <label name="count"/>
    <field name="count"/>
    <newline/>
    <label name="quantity"/>
    <field name="quantity"/>
    <label name="unit"/>
    <field name="unit"/>
</form>