firefox: extended and linked chameleon addon description

wiki/firefox.md

@@ -24,8 +24,11 @@ The add-ons are grouped thematically
 
 The following add-ons increase the security or privacy.
 
-- [Cameleon](https://addons.mozilla.org/en-GB/firefox/addon/chameleon-ext/)
+- [Chameleon](https://addons.mozilla.org/en-GB/firefox/addon/chameleon-ext/)
   spoofs your browser profile including user agent and screen size.
+  This add-on can also be used to avoid region locking by selecting IP ranges in the `Headers` tab.
+  An example for this is the range `124.81.64.0` to `124.81.127.255` that is assigned to brazilian
+  IP addresses.
 - [ClearURLs](https://addons.mozilla.org/en-GB/firefox/addon/clearurls) removes
   tracking elements from URLs.
 - [Consent-O-Matic](https://addons.mozilla.org/en-GB/firefox/addon/consent-o-matic)

wiki/vpn.md

@@ -4,6 +4,8 @@ A VPN is a virtual private network.
 It uses a secure connection between a computer and a network or two networks.
 It can be used to display another IP address but does not make tracking or
 fingerprinting of the device impossible.
+For the latter a plugin like [Chameleon for Firefox](/wiki/firefox.md#privacy-and-security-add-ons)
+can be used.
 VPNs feature a server and a client side.
 
 ## VPN implementations