Don't use firefox as the default user agent

modules/adblockplusorg/files/adblockplus.org

 server {
   root /var/www/adblockplus.org/httpdocs;
 
   location / {
     index index.php index index.html;
 
     if ($arg_a = "view") {
       rewrite ^(.*) $1? permanent;
     }
 
     set $preferredLang en;
     if ($http_accept_language ~ ^(\w\w)\b) {
       set $preferredLang $1;
     }
     if (!-f $document_root/static/$preferredLang/index) {
       set $preferredLang en;
     }
 
-    set $user_agent "firefox";
+    set $user_agent "";
+    if ($http_user_agent ~ \bGecko/\d+) {
+      set $user_agent "firefox";
+    }
     if ($http_user_agent ~ \bChrome/\d+) {
       set $user_agent "chrome";
     }
     if ($http_user_agent ~ \bPresto/\d+) {
       set $user_agent "opera";
     }
     if ($http_user_agent ~ \bAndroid\s.*\bAppleWebKit/\d+) {
       set $user_agent "android";
     }
 
+    set $platform "firefox";
+    if ($user_agent) {
+      set $platform $user_agent;
+    }
+
     if ($arg_a ~ ^(view|show)?$) {
-      rewrite ^/(index\.html)?$ /$preferredLang/$user_agent redirect;
-      rewrite ^/(\w\w(_\w\w)?)/?$ /$1/$user_agent redirect;
+      rewrite ^/(index\.html)?$ /$preferredLang/$platform redirect;
+      rewrite ^/(\w\w(_\w\w)?)/?$ /$1/$platform redirect;
     }
 
     rewrite ^/(\w\w(_\w\w)?)/installation$ /$1/ permanent;
     rewrite ^/anwiki/(.*) /$1 permanent;
 
     if (-f $request_filename) {
       break;
     }
     if (-d $request_filename) {
       break;
     }
 
     set $static_uri $uri;
-    set $platform $user_agent;
     if ($uri ~ ^/(\w\w(_\w\w)?)/(firefox|chrome|opera|android)/?$) {
       set $static_uri "/$1/";
       set $platform $3;
     }
     set $static "";
     if (-f "$document_root/static$static_uri") {
       set $static "ok";
     }
     if (-d "$document_root/static$static_uri") {
       set $static "ok";
@@ skipping 52 matching lines @@
     fastcgi_param GATEWAY_INTERFACE CGI/1.1;
     fastcgi_param SERVER_SOFTWARE nginx/$nginx_version;
 
     fastcgi_param REMOTE_ADDR $remote_addr;
     fastcgi_param REMOTE_PORT $remote_port;
     fastcgi_param SERVER_ADDR $server_addr;
     fastcgi_param SERVER_PORT $server_port;
     fastcgi_param SERVER_NAME $server_name;
   }
 }