wp-admin/includes/class-wp-filesystem-ftpsockets.php:509Checks if resource is a file.
$filestringbool public function is_file( $file ) { if ( $this->is_dir( $file ) ) { return false; } if ( $this->exists( $file ) ) { return true; } 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-ftpsockets.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.