When initializing, Wget will look for a global startup file, /usr/local/etc/wgetrc by default (or some prefix other than /usr/local, if Wget was not installed there) and read commands from there, if it exists.
Then it will look for the user's file. If the environmental variable
WGETRC is set, Wget will try to load that file. Failing that, no
further attempts will be made.
WGETRC is not set, Wget will try to load $HOME/.wgetrc.
The fact that user's settings are loaded after the system-wide ones means that in case of collision user's wgetrc overrides the system-wide wgetrc (in /usr/local/etc/wgetrc by default). Fascist admins, away!