I have an old module (from odoo15) where a field "unit" is added to the web view of an invoice and into the pdf file:
The second entry (field[@name='invoice_line_ids']/tree/field[@name='quantity']) to display this into the web view works fine. But the first entry (field[@name='line_ids']/tree/field[@name='quantity']) doesn't work, because the field line_ids can't be found. How can I find out the name of the corresponding field to add it to the pdf file?