Pre process a template that uses layout display I want to preprocess a user account display. I want to manipulate a field value at display time.
for example, i want to change:
field_prefered_color: redto :
field_prefered_color: red - Cool, that is used 5 times today.
If I don't use layout builder I can easily change that in
function mymodule_preprocess_user(&amp;$variables) {
  $variables['content']['field_prefered_color'][0]['#context'][['value'] .= t(' - Cool, that is used @times times today,['@times' =&gt; $times]);
}

But when I use layout builder, where can I find field_prefered_color to manipulate its output?
It appears quite easy to achieve what I want:
I needed to create a conditional field functionality. I know there is a module for that but at this time the module is not stable and not performing well with layout builder.
As indicated by @CG Monroe the last called template is field.html.twig.
If this is a user field the fully loaded user is available in:
$variables['elements']['#object']

So I could access all the user fields I needed to manipulate the field output in the preprocess function
function my_module_preprocess_field(&amp;$variables) {
  $field = $variables['elements']['#object']-&gt;field_some_other_field-&gt;value;
  // now I can manipulate the output of the field being viewed
  // the manipulation is needed because of the value of &quot;some-other-field&quot;
  $variables['items'][0]['content']['#context']['value'] = ' ***  ****';
  $variables['items'][0]['attributes']-&gt;addClass('my-module-field-manipulated');
}