Drupal 8 Twig
Filters
https://www.drupal.org/node/2357633
Translation
http://getlevelten.com/blog/mark-carver/drupal-8-twig-templates-and-translations
Functions
https://www.drupal.org/node/2486991
Attributes
https://www.drupal.org/node/2513632
Best Practices
Preprocess
https://www.drupal.org/node/2486991
Coding standards
https://www.drupal.org/node/1823416
Debugging
https://www.drupal.org/node/2358785 https://www.drupal.org/node/1903374 https://www.drupal.org/node/1906392
Naming Conventions
https://www.drupal.org/node/2354645 https://www.drupal.org/node/2186401