g1smd - 4:19 am on Apr 5, 2013 (gmt 0)
The file_exists and require are pretty standard PHP ways of doing things.
Whilst using ../../../ in a URL is a very bad idea, it's ta common way of doing things for PHP includes. Remember, this directive isn't going to generate a HTTP request, it's an internal filesystem fetch from one file to another within PHP. Since the software is installed in fixed folders, it's no big deal to use relative references to access other files within the filesystem.