Composer is the preferred dependency management solution for PHP, is used by Drupal core, and is becoming increasingly popular for managing the modules and themes used for a Drupal project.

The Render API consists of a standard format for describing data using structured arrays and a process for converting those arrays into the HTML a user sees when interacting with a Drupal site.

Cascading Style Sheets (CSS) files are added as an asset library through a theme’s libraries configuration file. HTML attributes, including classes and IDs, are commonly added in template files with Twig.