Opt-in telemetry, as well as unspecified telemetry while phoning home for license checks. I gather from memory that IDEs based on the IntelliJ platform scour the local network in search for other local network-connected machines running instances of their IDEs - e.g. in order to detect forbidden duplication of licenses. It is not apparently clear what details are(n't) transmitted back to the mothership.
This example requires a finer-grained analysis than the broadly chosen "opt-in" and "opt-out" categories to describe telemetry collection, and I wish for this information initiative to improve in clarity and thoroughness (e.g. does VSCode also scour the local network?).
Addendum: Thanks for asking for clarification. The grandparent comment could've been ambiguous in intent.
I did browse VS Code’s source code and I can’t recall seeing anything other than straightforward, albeit verbose, telemetry. When I find the time, I’ll reiterate on clarity! I’ll try to be more thorough, too, if time lets me. I want to verify everything before it goes online, which is time-consuming — an already scarce resource.
That’s very different isn’t it? Telemetry on an application you are a customer of, especially one with a GUI is expected. Tracking on a framework that you install, maybe even as a third party dependency, is not. Can you picture every major software dependency you use phoning home when you start a project?
The only real differences are who the user is (possibly a developer vs. an "end user") and how many hands are rifling through the user's pockets without permission. In an audience composed of mostly developers the attitude toward these scenarios may be different, but the fundamental ethical calculus is the same.