diff -r d29fbf97cc9f -r 3ef9aa7ad1fc mercurial/commands.py
--- a/mercurial/commands.py	Sun Jul 10 22:07:34 2016 +0900
+++ b/mercurial/commands.py	Sat Mar 19 17:19:03 2016 -0700
@@ -2423,7 +2423,8 @@
                  _('  location: %s\n'), extsource or "")
 
         fm.condwrite(ui.verbose and exttestedwith, 'testedwith',
-                 _('  tested with: %s\n'), ' '.join(exttestedwith))
+                     _('  tested with: %s\n'),
+                     fm.formatlist(exttestedwith, name='ver'))
 
         fm.condwrite(ui.verbose and extbuglink, 'buglink',
                  _('  bug reporting: %s\n'), extbuglink or "")