wp-includes/theme.php:1605Registers a selection of default headers to be displayed by the custom header admin UI.
$headersarrayfunction register_default_headers( $headers ) { global $_wp_default_headers; $_wp_default_headers = array_merge( (array) $_wp_default_headers, (array) $headers );}Introduced in 3.0.0. 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.