wp-includes/block-template-utils.php:1409Prints the header block template part.
function block_header_area() { block_template_part( 'header' );}Introduced in 5.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/block-template-utils.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.