Twig templates are not loading I am using Drupal 8 from github:drupal/drupal@a9ac0fbf17, but having problems creating custom template, using Twig template engine.

Here is template file structure:

.
├── README.txt
├── screenshot.png
├── templates
│   └── html.html.twig
└── custom.info.yml  

html.html.twig file is not being loaded. I have tried to change ownership/permission of the files, but it didn't help. I turned on twig_debug and getting:

&lt;!-- THEME DEBUG --&gt;
&lt;!-- CALL: _theme('html') --&gt;
&lt;!-- FILE NAME SUGGESTIONS:
   * html--front.html.twig
   * html--node.html.twig
   x html.html.twig
--&gt;
&lt;!-- BEGIN OUTPUT from 'core/modules/system/templates/html.html.twig' --&gt;


which, I assume means it is loading default template from core/modules/system/templates/.

Here is the content of my html.html.twig:

{#
/**
 * @file
 * basic html structure of a single Drupal page.
 */
 #}

 &lt;!doctype html&gt;
 &lt;html lang="en"&gt;
 &lt;head {{ html_attributes }}&gt;
   &lt;title&gt;{{ head_title }}&lt;/title&gt;
   {{ page.head }}
   {{ page.styles }}
   {{ page.scripts }}
&lt;/head&gt;
&lt;body {{ attributes }}&gt;
    {{ page_top }}
    {{ page.content }}
    {{ page_bottom }}
    {{ page.scripts('footer') }}
&lt;/body&gt;
&lt;/html&gt;


What might I be missing? let me know if you need more info.
Thanks
To disable cache for development(tiwg + Drupal cache) :

first copy and rename the sites/example.settings.local.php to be sites/default/settings.local.php

then open settings.php file in sites/default and uncomment these lines:

# if (file_exists(__DIR__ . '/settings.local.php')) {
#   include __DIR__ . '/settings.local.php';
# }


Now open settings.local.php and change the below lines to "TRUE".

$config['system.performance']['css']['preprocess'] = FALSE;
$config['system.performance']['js']['preprocess'] = FALSE;


and uncomment all these to Disable the render cache and Disable Dynamic Page Cache

# $settings['cache']['bins']['render'] = 'cache.backend.null';
# $settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.null';


for twig cache open "development.services.yml" and update the below parameters.

  twig.config:
    debug : true
    auto_reload: true
    cache: false