Diff is not currently PSR-0 [0] compliant. More recently introduced classes typically are, though the initial core of the library is not. Some classes will need to be moved into sub namespaces to be compliant.
Once this is done, the manually maintained autoloading list at Diff.classes.php can be removed.
[0] https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md
Version: master
Severity: normal