diff -r 1f7c077e0640 -r 40411ad2f5d2 mercurial/filemerge.py
--- a/mercurial/filemerge.py	Fri Oct 23 15:27:33 2020 -0700
+++ b/mercurial/filemerge.py	Fri Oct 23 15:59:32 2020 -0700
@@ -831,7 +831,7 @@
     ca = fca.changectx()
 
     ui = repo.ui
-    template = ui.config(b'ui', b'mergemarkertemplate')
+    template = ui.config(b'command-templates', b'mergemarker')
     if tool is not None:
         template = _toolstr(ui, tool, b'mergemarkertemplate', template)
     template = templater.unquotestring(template)
@@ -1100,7 +1100,7 @@
             labeltool = None
             if markerstyle != b'basic':
                 # respect 'tool's mergemarkertemplate (which defaults to
-                # ui.mergemarkertemplate)
+                # command-templates.mergemarker)
                 labeltool = tool
             if internalmarkerstyle != b'basic' or markerstyle != b'basic':
                 premergelabels = _formatlabels(