diff -r f636103c4d67 -r 861fe9273d57 mercurial/unionrepo.py
--- a/mercurial/unionrepo.py	Tue Oct 10 10:56:42 2023 +0200
+++ b/mercurial/unionrepo.py	Tue Oct 10 10:58:28 2023 +0200
@@ -213,15 +213,6 @@
             self, opener, self._revlog.radix, manifest2, linkmapper
         )
 
-    # XXX small hack to work around the use of manifest.manifestrevlog
-    @property
-    def _generaldelta(self):
-        return self._revlog.delta_config.general_delta
-
-    @_generaldelta.setter
-    def _generaldelta(self, value):
-        self._revlog.delta_config.general_delta = value
-
 
 class unionfilelog(filelog.filelog):
     def __init__(self, opener, path, opener2, linkmapper, repo):