storage_backend_sftp/views/backend_storage_view.xml
<?xml version="1.0" encoding="UTF-8"?>
<odoo>
<record id="storage_backend_view_form" model="ir.ui.view">
<field name="model">storage.backend</field>
<field name="inherit_id" ref="storage_backend.storage_backend_view_form" />
<field name="arch" type="xml">
<group name="config" position="after">
<group name="sftp" string="SFTP" attrs="{'invisible': [('backend_type', '!=', 'sftp')]}">
<field name="sftp_server"/>
<field name="sftp_port"/>
<field name="sftp_login"/>
<field name="sftp_password"/>
<field name="sftp_auth_method"/>
</group>
</group>
</field>
</record>
</odoo>