Where is Chrome Extension's Setting Files/Databases?
~/Library/Application Support/Google/Chrome/Default/Extensions is for the static extension files only. Storage space for Extensions is found in ~/Library/Application Support/Google/Chrome/Default/Local Storage:

IanCsiMac:~/Library/Application Support/Google/Chrome/Default/Local Storage |ruby-2.1.2|
&gt; ls | grep redditenhancement
http_redditenhancementsuite.com_0.localstorage
http_redditenhancementsuite.com_0.localstorage-journal