http://l3tczdiiwoo63iwxty4lhs6p7eaxop5micbn7vbliydgv63x5zrrrfyd.onion/4.0.0/user-manual/appendix.html
Next, Privoxy checks to see if the URL matches any "+block" patterns. If so, the URL is then blocked,
and the remote web server will not be contacted. "+handle-as-image" and "+handle-as-empty-document" are then checked, and if there is no match, an HTML "BLOCKED" page is sent back to the browser.