The list is also empty with my account logging in kbin.social.
Makes perfect sense, tbh. The list of instances federating with yours will get too large pretty quickly to have it listed in the sidebar -see the one of my instance, literally hundreds-. A sidebar is a terrible place for that information.
I want admins to publish their configs to federate/block other instances though they have no duty to do. :D
Maybe you can ask for the feature in the project site and future versions of Kbin will have it and no need for admins to include it themselves. I believe the developers had the intention to show the instances connected -as seen by the sidebar thing-, so maybe it’s just asking for a page similar to Lemmy’s one. Though it is possible that kbin.social admins do not want to show it and are actually hiding it.