PHP CMS still powering ~40% of the open web. Open-source core; commercial ecosystem (Automattic) around it.
From Wikipedia
WordPress is a web content management system. It was originally created as a tool to publish blogs but has evolved to support publishing other web content, including more traditional websites, mailing lists, Internet forums, media galleries, membership sites, learning management systems, and online stores. Available as free and open-source software, WordPress is among the most popular content management systems – it was used by 22.52% of the top one million websites as of December 2024.