wp-admin/includes/class-wp-filesystem-ssh2.php:584Checks if resource is a file.
$filestringbool public function is_file( $file ) { return is_file( $this->sftp_path( $file ) ); }Introduced in 2.7.0. 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-ssh2.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.