Yes, the PIO IDE Terminal shows the environment variables values after a restart if I query them like that.
I tried setting the variables with and without my credentials, both variants didn’t enable PIO IDE to connect to the internet.
Giving the proxy-settings to pip in a similar form --proxy="http://<username>:<password>@proxy.hs-karlsruhe.de" works to download python packages.
I tried to use the request-package in python like suggested on your link which resulted in an error:
requests.exceptions.ProxyError: HTTPSConnectionPool(host=‘proxy.hs-karlsruhe.de’, port=8888): Max retries exceeded with url: http://example.org/ (Caused by ProxyError(‘Cannot connect to proxy.’, error(‘Tunnel connection failed: 403 Forbidden’,)))
EDIT: I fixed it
http://<username>:<password>@proxy.hs-karlsruhe.de:8888/
Environment variable has to be formated exactly that way. I never thought the last slash could be important…