I mean the commanders list in the Comms panel where you can talk to specific players when they are targeted or block/report players, if that's any clearer. It's an old beta image but this is what I mean.
It'll pop up if (and only if) there are commanders in the same instance as you when you select the com panel, regardless of whether or not you have them targeted.
Edit: or if you have friends online as shown in the screenshot.