Understanding Twig namespaces
Understanding what Twig namespaces are and why you would use them
Registering Twig namespaces
Understanding how to create the Twig namespaces used in the @namespace/template.html.twig syntax
Twig filters: add(), set(), recursive_merge()
Twig filters added by Components module
Twig functions: template()
Twig functions added by Components module
Upgrade Guide: 1.x to 2.x
Short HowTo's to facilitate upgrading from 1.x to 2.x
