CoreBoost v3.3.0

✨ Added - LCP Optimizations for CSS Background Video Heroes

• preconnect to i.ytimg.com emitted automatically when Smart YouTube Blocking is enabled. YouTube fallback thumbnails (the LCP element on video-hero pages) are served from i.ytimg.com. Without a preconnect, the browser incurs a full DNS + TCP + TLS cold-start cost (~100–150 ms) before the first byte of the LCP image arrives. The tag is output at wp_head priority 1 alongside existing Google/Adobe Fonts preconnects in Font_Optimizer::add_font_preconnects().
• Hero_Optimizer::is_url_preloaded() — new public static method that tracks every URL emitted as a <link rel="preload"> tag. Allows Resource_Remover to avoid injecting a duplicate preload in the output buffer when the hero optimizer already handled it during wp_head.

🐛 Fixed - Video Hero Detection & LCP Fallback Quality

• smart_youtube_blocking now defaults to true in class-config.php. The setting was false by default, meaning the PHP data-settings stripping never ran on any fresh install. The output buffer never started (it requires at least one optimization flag to be enabled), so background_video_link was never stripped, the YouTube IFrame API loaded on page load, and the fallback image preload tag was never injected — causing the 1,410 ms resource load delay on video-hero pages.
• YouTube thumbnail upgraded from hqdefault.jpg (480×360) to maxresdefault.jpg (1280×720) in extract_youtube_thumbnail_url(). Full-width hero video backgrounds render at the larger size; preloading the low-res thumbnail caused the browser to make a second fetch for the high-res version, wasting the preload entirely and extending resource load duration.
• get_elementor_video_fallback() and get_video_hero_fallback_image() now scan recursively (up to 4 levels deep, up to 5 root elements). Previously both methods only inspected $elements[0] — the first top-level element — missing video backgrounds nested inside Elementor Flexbox containers (container > container > section). The recursive approach matches the depth already used by search_elementor_hero_advanced().
• find_background_videos() now counts both section and container elTypes at root depth, and scans up to 5 root elements (was 3 section-type only). Modern Elementor Flexbox layouts use elType === 'container', so the previous $section_count check never incremented, effectively allowing the scan to either run too deep or miss the hero in container-based layouts. Max recursion depth also raised from 3 to 4 for consistency with other detection methods.
• Duplicate fallback preload tag eliminated. When both preload_method = video_hero and smart_youtube_blocking are active, both Hero_Optimizer::preload_video_hero() (wp_head priority 1) and Resource_Remover::remove_youtube_background_iframes() (output buffer) could emit a <link rel="preload"> for the same URL. Resource_Remover now calls Hero_Optimizer::is_url_preloaded() before injecting and skips the tag if it was already output.

Files Modified

• includes/core/class-config.php — smart_youtube_blocking default false → true
• includes/public/class-hero-optimizer.php — extract_youtube_thumbnail_url() thumbnail quality; get_elementor_video_fallback() and get_video_hero_fallback_image() recursive scan; find_background_videos() container support + depth; output_preload_tag() deduplication tracking; new is_url_preloaded() static method
• includes/public/class-resource-remover.php — fallback preload deduplication check
• includes/public/class-font-optimizer.php — i.ytimg.com preconnect in add_font_preconnects()

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