wp-admin/includes/class-wp-filesystem-base.php:554Changes current directory.
$dirstringbool public function chdir( $dir ) { return false; }Introduced in 2.5.0. 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-filesystem-base.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.