pos/pos_remove_pos_category/views/pos_category.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>

        <template id="assets_backend" name="pos_remove_pos_category assets" inherit_id="web.assets_backend">
            <xpath expr="." position="inside">
                <script type="text/javascript" src="/pos_remove_pos_category/static/src/js/pos_remove_pos_category.js"></script>
            </xpath>
            <xpath expr="//script[@src='/point_of_sale/static/src/js/widgets.js']" position="attributes">
                <attribute name="src">/pos_remove_pos_category/static/src/js/widgets2.js</attribute>
            </xpath>
        </template>

        <record id="product_category_form_view" model="ir.ui.view">
            <field name="model">product.category</field>
            <field name="inherit_id" ref="product.product_category_form_view"/>
            <!-- Priority to avoid to break account and logistics fields-->
            <field name="priority">20</field>
            <field name="arch" type="xml">
                <xpath expr="//group[@name='parent']" position="inside">
                    <field name="image"
                           widget="image"
                           class="oe_left oe_avatar"
                           options='{"size": [100, 100]}' />
                    <field name="available_in_pos"/>
                </xpath>
            </field>
        </record>

        <record id="product_category_list_view" model="ir.ui.view">
            <field name="model">product.category</field>
            <field name="inherit_id" ref="product.product_category_list_view"/>
            <field name="arch" type="xml">
                <xpath expr="//field[@name='complete_name']" position="after">
                    <field name="available_in_pos" string="Available in POS"/>
                </xpath>
            </field>
        </record>

    </data>
</openerp>