--- a/mercurial/commands.py	Wed Feb 14 08:14:46 2024 +0100
+++ b/mercurial/commands.py	Fri Feb 23 04:26:03 2024 +0100
@@ -7730,7 +7730,7 @@
     _(b'[-u] FILE...'),
     helpcategory=command.CATEGORY_IMPORT_EXPORT,
 )
-def unbundle(ui, repo, fname1, *fnames, **opts):
+def unbundle(ui, repo, fname1, *fnames, _unbundle_source=b'unbundle', **opts):
     """apply one or more bundle files
 
     Apply one or more bundle files generated by :hg:`bundle`.
@@ -7758,7 +7758,11 @@
                     txnname = b'unbundle\n%s' % urlutil.hidepassword(url)
                 with repo.transaction(txnname) as tr:
                     op = bundle2.applybundle(
-                        repo, gen, tr, source=b'unbundle', url=url
+                        repo,
+                        gen,
+                        tr,
+                        source=_unbundle_source,  # used by debug::unbundle
+                        url=url,
                     )
             except error.BundleUnknownFeatureError as exc:
                 raise error.Abort(