diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -484,6 +484,14 @@ coreconfigitem('ui', 'merge',
 coreconfigitem('ui', 'mergemarkers',
     default='basic',
 )
+coreconfigitem('ui', 'mergemarkertemplate',
+    default=('{node|short} '
+            '{ifeq(tags, "tip", "", '
+            'ifeq(tags, "", "", "{tags} "))}'
+            '{if(bookmarks, "{bookmarks} ")}'
+            '{ifeq(branch, "default", "", "{branch} ")}'
+            '- {author|user}: {desc|firstline}')
+)
 coreconfigitem('ui', 'nontty',
     default=False,
 )
diff --git a/mercurial/filemerge.py b/mercurial/filemerge.py
--- a/mercurial/filemerge.py
+++ b/mercurial/filemerge.py
@@ -555,13 +555,6 @@ def _formatconflictmarker(repo, ctx, tem
     # 8 for the prefix of conflict marker lines (e.g. '<<<<<<< ')
     return util.ellipsis(mark, 80 - 8)
 
-_defaultconflictmarker = ('{node|short} '
-                          '{ifeq(tags, "tip", "", '
-                           'ifeq(tags, "", "", "{tags} "))}'
-                          '{if(bookmarks, "{bookmarks} ")}'
-                          '{ifeq(branch, "default", "", "{branch} ")}'
-                          '- {author|user}: {desc|firstline}')
-
 _defaultconflictlabels = ['local', 'other']
 
 def _formatlabels(repo, fcd, fco, fca, labels):
@@ -574,7 +567,7 @@ def _formatlabels(repo, fcd, fco, fca, l
     ca = fca.changectx()
 
     ui = repo.ui
-    template = ui.config('ui', 'mergemarkertemplate', _defaultconflictmarker)
+    template = ui.config('ui', 'mergemarkertemplate')
     template = templater.unquotestring(template)
     tmpl = formatter.maketemplater(ui, template)