With #188270, extensions can now contribute tunnel factories. However, extensions doing this need to get activated on * / startupFinished to be shown there. It'd be nice if there was some kind of "tunnel" activation event that would only pick up when a tunnel or requested, or perhaps if the Ports view is interacted with, to avoid this.

Mentioned in https://github.com/microsoft/vscode-remote-tunnels/pull/661#discussion_r1272804131