wp-admin/includes/class-wp-upgrader.php:1099Releases an upgrader lock.
$lock_namestringbool public static function release_lock( $lock_name ) { return delete_option( $lock_name . '.lock' ); }Introduced in 4.5.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/class-wp-upgrader.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.