 <p>All associated data with an extension is removed when the extension is uninstalled. You can verify this by visiting your Chrome profile directory, and descend in <code>Local Storage</code>. You'll see a SQLLite database (eg. <code>chrome-extension_lndfmdleiloedhcbmjofibnflfbjhpha_0.localstorage</code>).</p> <p>After removing the extension, this database disappears.</p>