In your .htaccess file you might have a rule which ensures that all files and folders matching a particular path be handled by WordPress or Ghost. An example of such a rule would be the following snippet:
RewriteCond %{REQUEST_URI} !^/(contact.php)$
RewriteCond %{REQUEST_URI} !^/[0-9]+..+.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}.txt(?: Comodo DCV)?$
RewriteRule ^(.*)$ http://your-domain.com:62914/$1 [P]
The following part of the snippet in the .htaccess file ensures that the contact.php file is excluded from the rewrite rule:
RewriteCond %{REQUEST_URI} !^/(contact.php)$
This is particularly useful when you need to exclude a file from being "managed" by WordPress, Ghost or any other CMS for that matter.
To exlcude a whole folder as well as all files therein, the top rewrite condition from the snippet above will look as follows:
RewriteCond %{REQUEST_URI} !^/(YOUR-DIRECTORY|YOUR-DIRECTORY/.*)$