Environment Proxy allows you to sets proxy settings from environment variables.
This is mostly useful for Unix/Linux machines, where the proxy settings are set by environment variables like http_proxy, https_proxy etc. (Konqueror has a similar feature "Use preset proxy environment variables"). This makes it easier for administrators to control the proxy settings for several applications (gaim, konqueror, firefox, thunderbird etc.)
The default environment variables used are:
http_proxy
https_proxy
ftp_proxy
no_proxy
These defaults can be changed in the preferences of this extension. If any of the environment variables are found, they are set in the proxy settings and used, if not found, a direct internet connection is used.