I would like to create a custom template for the user profile view. With the help of "Theme debug" I figured out that I need to create a template named html--user.html.twig, but even if I copy all content of page.html.twig to my new template, I do get a blank page for any user profile now. Can anyone tell me what I'm doing wrong? I cleared all caches though.
Which content do I have to copy to a custom template (suggested file name)?
html--user.html.twig would be the template file used instead of html.html.twig when viewing a user profile (for example, for http://example.com/user/1). It is not the template file that shows the content of a user profile, but it's the template file that contains the basic structure of a Drupal page; in fact, its default content is the following one.
<!DOCTYPE html>
<html{{ html_attributes }}>
<head>
<head-placeholder token="{{ placeholder_token|raw }}">
<title>{{ head_title|safe_join(' | ') }}</title>
<css-placeholder token="{{ placeholder_token|raw }}">
<js-placeholder token="{{ placeholder_token|raw }}">
</head>
<body{{ attributes }}>
<a href="#main-content" class="visually-hidden focusable">
{{ 'Skip to main content'|t }}
</a>
{{ page_top }}
{{ page }}
{{ page_bottom }}
<js-bottom-placeholder token="{{ placeholder_token|raw }}">
</body>
</html>
page.html.twig is the template file for a generic page; that is why you are getting a white page for user profile pages.
The template file for a user profile is user.html.twig, and its default content is the following one.
<article{{ attributes }}>
{% if content %}
{{- content -}}
{% endif %}
</article>
As you see the variable it receives are completely different from the ones the other two template files (html.html.twig and page.html.twig) receive. That is why using the wrong template gives you a blank page.
