diff -r af83a0ed0afb -r 32bc3815efae mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Thu May 10 21:00:58 2018 +0900
+++ b/mercurial/debugcommands.py	Thu May 10 21:08:32 2018 +0900
@@ -3017,10 +3017,12 @@
 
                 if isinstance(res, wireprotov2peer.commandresponse):
                     val = list(res.cborobjects())
-                    ui.status(_('response: %s\n') % stringutil.pprint(val))
+                    ui.status(_('response: %s\n') %
+                              stringutil.pprint(val, bprefix=True))
 
                 else:
-                    ui.status(_('response: %s\n') % stringutil.pprint(res))
+                    ui.status(_('response: %s\n') %
+                              stringutil.pprint(res, bprefix=True))
 
         elif action == 'batchbegin':
             if batchedcommands is not None:
@@ -3092,7 +3094,8 @@
                 continue
 
             if res.headers.get('Content-Type') == 'application/mercurial-cbor':
-                ui.write(_('cbor> %s\n') % stringutil.pprint(cbor.loads(body)))
+                ui.write(_('cbor> %s\n') %
+                         stringutil.pprint(cbor.loads(body), bprefix=True))
 
         elif action == 'close':
             peer.close()