I added a custom field to attribute add/edit form using these instructions: https://magento.stackexchange.com/a/238731 and Magento 2.2.6 : Add custom field in product attribute add form - Is not render the database value on edit
So I created an extension with that code and I do see the new field in the product attribute add/edit form, but the value doesn't get saved.
So the part that's missing is how to save the value to the DB. How can I accomplish that?
Thank you