Update:

Checkbox appearance is affected by javascript described in addons /base_import/static/src/js/import_action.js

$fields.each(function (k,v) {

var filtered_data = self.generate_fields_completion(result, k);

var $thing = $();

var bind = function (d) {};

if (config.isDebug()) {

$thing = $(QWeb.render('ImportView.create_record_option')).insertAfter(v).hide();

bind = function (data) {

switch (data.type) {

case 'many2one': case 'many2many':

$thing.find('input').attr('field', data.id);

$thing.show();

break;

default:

$thing.find('input').attr('field', '').prop('checked', false);

$thing.hide();

}

}

}

I am trying to modify this file, but so far I have been able to influence the appearance of the checkbox in developer mode. Unfortunately, I'm not a javascript professional. I will be looking for a way to display a checkbox without developer mode