M docs/activitypub.7 → docs/activitypub.7

@@ -131,6 +131,15 @@ .It Document
 Plain text and images in jpeg, gif, png, and webp formats are supported.
 Other formats are linked to origin.
 .El
+.Ss EXTENSIONS
+Honk also supports a
+.Vt Ping
+activity and will respond with a
+.Vt Pong
+activity.
+This is useful for debugging networking connectivity issues without
+visible side effects.
+See ping.txt for details.
 .Ss SECURITY
 Honk uses http signatures.
 .Ss WEBFINGER