Via SSH:

1.) cd /var/www/dekiwiki/bin/_x002F_deki_x002F_pagesubservice/subscriptions 
2.) cd into the directory for the default database
3.) Each file here is listed as "user_[x].xml", and contains data showing the subscriptions for each user marked as page IDs. Please note when it references a depth of "infinity", it indicates the user is subscribed to the indicated page and all sub-pages. A depth of "0" is simply a subscription to a single page. 
4a.) If you know the user ID, and wish to search for their subscription, display the contents of the necessary file via a command like: 

  cat user_1.xml  

4b.) If you know the page ID and want to see who is subscribed, perform a search of this directory like so:

   grep 'id="xxx"' *   

...this will search for the term id="xxx" where xxx is the page ID in all files in the current directory. Please note the syntax must have the search term surrounded by single quotes as so: ' id="xxx" ', though don't include any spaces--spaces shown here are simply for visual purposes.