diff --git a/mercurial/filelog.py b/mercurial/filelog.py
--- a/mercurial/filelog.py
+++ b/mercurial/filelog.py
@@ -42,6 +42,15 @@ class filelog:
         opts = opener.options
         self._fix_issue6528 = opts.get(b'issue6528.fix-incoming', True)
 
+    def get_revlog(self):
+        """return an actual revlog instance if any
+
+        This exist because a lot of code leverage the fact the underlying
+        storage is a revlog for optimization, so giving simple way to access
+        the revlog instance helps such code.
+        """
+        return self._revlog
+
     def __len__(self):
         return len(self._revlog)
 
diff --git a/mercurial/interfaces/repository.py b/mercurial/interfaces/repository.py
--- a/mercurial/interfaces/repository.py
+++ b/mercurial/interfaces/repository.py
@@ -1404,6 +1404,14 @@ class imanifeststorage(interfaceutil.Int
         This one behaves the same way, except for manifest data.
         """
 
+    def get_revlog():
+        """return an actual revlog instance if any
+
+        This exist because a lot of code leverage the fact the underlying
+        storage is a revlog for optimization, so giving simple way to access
+        the revlog instance helps such code.
+        """
+
 
 class imanifestlog(interfaceutil.Interface):
     """Interface representing a collection of manifest snapshots.
diff --git a/mercurial/manifest.py b/mercurial/manifest.py
--- a/mercurial/manifest.py
+++ b/mercurial/manifest.py
@@ -1617,6 +1617,15 @@ class manifestrevlog:
         self.index = self._revlog.index
         self._generaldelta = self._revlog._generaldelta
 
+    def get_revlog(self):
+        """return an actual revlog instance if any
+
+        This exist because a lot of code leverage the fact the underlying
+        storage is a revlog for optimization, so giving simple way to access
+        the revlog instance helps such code.
+        """
+        return self._revlog
+
     def _setupmanifestcachehooks(self, repo):
         """Persist the manifestfulltextcache on lock release"""
         if not util.safehasattr(repo, '_wlockref'):
diff --git a/mercurial/revlog.py b/mercurial/revlog.py
--- a/mercurial/revlog.py
+++ b/mercurial/revlog.py
@@ -663,6 +663,10 @@ class revlog:
         # revlog header -> revlog compressor
         self._decompressors = {}
 
+    def get_revlog(self):
+        """simple function to mirror API of other not-really-revlog API"""
+        return self
+
     @util.propertycache
     def revlog_kind(self):
         return self.target[0]