wp-includes/theme.php:1818Prints the markup for a custom header.
function the_custom_header_markup() { $custom_header = get_custom_header_markup(); if ( empty( $custom_header ) ) { return; } echo $custom_header; if ( is_header_video_active() && ( has_header_video() || is_customize_preview() ) ) { wp_enqueue_script( 'wp-custom-header' ); wp_localize_script( 'wp-custom-header', '_wpCustomHeaderSettings', get_header_video_settings() ); }}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.