WordPress 5.9 introduced a new way to build websites: Full Site Editing. It was a turning point for WordPress users because it completely changed the way WordPress themes are built and work.
The introduction of FSE also introduced a distinction between themes that fully support the new site-building features, also known as Block Themes, and the traditional PHP-based themes, which we now call Classic Themes.
Over time, many features built for Block Themes have been extended to Classic Themes. This has resulted in a third category of themes, Hybrid Themes, that are still built with the logic and structure of
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