diff -r 4c041c71ec01 -r 64cd1496bb70 mercurial/revlog.py
--- a/mercurial/revlog.py	Tue Apr 06 05:20:24 2021 +0200
+++ b/mercurial/revlog.py	Thu Apr 08 19:00:21 2021 +0200
@@ -559,6 +559,10 @@
         self._decompressors = {}
 
     @util.propertycache
+    def revlog_kind(self):
+        return self.target[0]
+
+    @util.propertycache
     def _compressor(self):
         engine = util.compengines[self._compengine]
         return engine.revlogcompressor(self._compengineopts)