I have heard these days a lot of programmers in these companies do all of their development inside of docker or VMs so they can actually get stuff done without filling out an approval form to update their linter.
At least where I worked, the HTTPS proxy blocked most downloads. Most software these days can install fine for a local user. It's more a matter of getting the installer. But, it was a pretty easy process for non-GPL3 open-source software: fill out a web form with the URL for the installer/source tarball and a URL for the license, wait a few hours, and the installer has been virus scanned and in available in the internal mirror repository of installers.
We had internal repositories. You go to a website, give a URL for the library or executable/installer you want to use, and a URL for the license it's under. A few hours later, you get an email that it has been approved, downloaded, virus scanned, and is available from the internal repository.
I think the HTTPS proxies necessary to reach the outside would block the communications necessary for Copilot to work.