Apache is a free and open-source cross-platform web server software.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
RankMath SEO is a search engine optimisation plugin for WordPress.
WP Rocket is a caching and performance optimisation plugin to improve the loading speed of WordPress websites.