Zend certified PHP/Magento developer

Remove proxy set during Ubuntu install

During installation of Ubuntu server 18.04 I filled in our corporate proxy, but now I would like to remove it from everywhere the installer has set it to. I cant find anywhere where the proxy is set though. Locations I checked:
~/.bashrc
/etc/environment
env
In any of these there is no mention of proxy. Do you have any more suggestions what to check to completely remove the proxy setting from the server?