wp-includes/theme.php:2030Fetches the saved Custom CSS content for rendering.
$stylesheetstringoptional''stringOne hook fires while wp_get_custom_css() runs, in this order:
Filters the custom CSS output into the head element.
function wp_get_custom_css( $stylesheet = '' ) { $css = ''; if ( empty( $stylesheet ) ) { $stylesheet = get_stylesheet(); } $post = wp_get_custom_css_post( $stylesheet ); if ( $post ) { $css = $post->post_content; } /** * Filters the custom CSS output into the head element. * * @since 4.7.0 * * @param string $css CSS pulled in from the Custom CSS post type. * @param string $stylesheet The theme stylesheet name. */ $css = apply_filters( 'wp_get_custom_css', $css, $stylesheet ); return $css;}Introduced in 4.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/theme.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.