Epic has responded:
We use a tracking pixel (tracking.js) for our Support-A-Creator program so we can pay creators. We also track page statistics.
The UDP traffic highlighted in this post is a launcher feature for communication with the Unreal Editor. The source of the underlying system is available on github.
The majority of the launcher UI is implemented using web technology that is being rendered by Chromium (which is open source). The root certificate and cookie access mentioned above is a result of normal web browser start up.
The launcher scans your active processes to prevent updating games that are currently running. This information is not sent to Epic.
We only import your Steam friends with your explicit permission. The launcher makes an encrypted local copy of your localconfig.vdf Steam file. However information from this file is only sent to Epic if you choose to import your Steam friends, and then only hashed ids of your friends are sent and no other information from the file.
Epic is controlled by Tim Sweeney. We have lots of external shareholders, none of whom have access to customer data.
VP of Engineering
Epic Games Inc.