Apache is a free and open-source cross-platform web server software.
Drupal is a free and open-source web content management framework.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
WP Rocket is a caching and performance optimisation plugin to improve the loading speed of WordPress websites.