wp-includes/class-wp-customize-manager.php:2057Prints CSS for loading indicators for the Customizer preview.
public function customize_preview_loading_style() { ?> <style> body.wp-customizer-unloading { opacity: 0.25; cursor: progress !important; -webkit-transition: opacity 0.5s; transition: opacity 0.5s; } body.wp-customizer-unloading * { pointer-events: none !important; } form.customize-unpreviewable, form.customize-unpreviewable input, form.customize-unpreviewable select, form.customize-unpreviewable button, a.customize-unpreviewable, area.customize-unpreviewable { cursor: not-allowed !important; } </style> <?php }Introduced in 4.2.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-customize-manager.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.