wp-includes/functions.php:7168Sends a HTTP header to disable content type sniffing in browsers which support it.
function send_nosniff_header() { header( 'X-Content-Type-Options: nosniff' );}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/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.