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.