Every instance should have a nodeinfo or link to it at /.well-known/nodeinfo, but despite this meta forum being federated, it currently returns 404. Here is mastodon.social’s nodeinfo for reference: https://mastodon.social/.well-known/nodeinfo
You could re-assign this request to category Plugin, ActivityPub Plugin. Active users of the ActivityPub plugin and the developers are available there, I guess …
Thanks for the feature request! We’ll be looking at adding a nodeinfo
endpoint soon.