wp-includes/theme.php:1457Checks if random header image is in use.
$typestringoptional'any'boolfunction is_random_header_image( $type = 'any' ) { $header_image_mod = get_theme_mod( 'header_image', get_theme_support( 'custom-header', 'default-image' ) ); if ( 'any' === $type ) { if ( 'random-default-image' === $header_image_mod || 'random-uploaded-image' === $header_image_mod || ( empty( $header_image_mod ) && '' !== get_random_header_image() ) ) { return true; } } else { if ( "random-$type-image" === $header_image_mod ) { return true; } elseif ( 'default' === $type && empty( $header_image_mod ) && '' !== get_random_header_image() ) { return true; } } return false;}Introduced in 3.2.0. 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.