diff --git a/mercurial/filelog.py b/mercurial/filelog.py
--- a/mercurial/filelog.py
+++ b/mercurial/filelog.py
@@ -53,10 +53,6 @@
     def linkrev(self, rev):
         return self._revlog.linkrev(rev)
 
-    # Unused.
-    def flags(self, rev):
-        return self._revlog.flags(rev)
-
     def commonancestorsheads(self, node1, node2):
         return self._revlog.commonancestorsheads(node1, node2)
 
diff --git a/mercurial/repository.py b/mercurial/repository.py
--- a/mercurial/repository.py
+++ b/mercurial/repository.py
@@ -502,9 +502,6 @@
     def linkrev(rev):
         """Obtain the changeset revision number a revision is linked to."""
 
-    def flags(rev):
-        """Obtain flags used to affect storage of a revision."""
-
     def iscensored(rev):
         """Return whether a revision's content has been censored."""
 
diff --git a/mercurial/testing/storage.py b/mercurial/testing/storage.py
--- a/mercurial/testing/storage.py
+++ b/mercurial/testing/storage.py
@@ -96,15 +96,6 @@
             with self.assertRaises(IndexError):
                 f.linkrev(i)
 
-        self.assertEqual(f.flags(nullrev), 0)
-
-        for i in range(-5, 5):
-            if i == nullrev:
-                continue
-
-            with self.assertRaises(IndexError):
-                f.flags(i)
-
         self.assertFalse(f.iscensored(nullrev))
 
         for i in range(-5, 5):
@@ -193,11 +184,6 @@
         with self.assertRaises(IndexError):
             f.linkrev(1)
 
-        self.assertEqual(f.flags(0), 0)
-
-        with self.assertRaises(IndexError):
-            f.flags(1)
-
         self.assertFalse(f.iscensored(0))
 
         with self.assertRaises(IndexError):
@@ -290,13 +276,6 @@
         with self.assertRaises(IndexError):
             f.linkrev(3)
 
-        self.assertEqual(f.flags(0), 0)
-        self.assertEqual(f.flags(1), 0)
-        self.assertEqual(f.flags(2), 0)
-
-        with self.assertRaises(IndexError):
-            f.flags(3)
-
         self.assertFalse(f.iscensored(0))
         self.assertFalse(f.iscensored(1))
         self.assertFalse(f.iscensored(2))
@@ -957,7 +936,6 @@
             f.addrevision(stored1, tr, 1, node0, nullid,
                           flags=revlog.REVIDX_ISCENSORED)
 
-        self.assertEqual(f.flags(1), revlog.REVIDX_ISCENSORED)
         self.assertTrue(f.iscensored(1))
 
         self.assertEqual(f.revision(1), stored1)
diff --git a/tests/simplestorerepo.py b/tests/simplestorerepo.py
--- a/tests/simplestorerepo.py
+++ b/tests/simplestorerepo.py
@@ -228,7 +228,7 @@
 
         return self._indexbyrev[rev][b'linkrev']
 
-    def flags(self, rev):
+    def _flags(self, rev):
         validaterev(rev)
 
         return self._indexbyrev[rev][b'flags']
@@ -243,8 +243,8 @@
         validaterev(baserev)
         validaterev(rev)
 
-        if ((self.flags(baserev) & revlog.REVIDX_RAWTEXT_CHANGING_FLAGS)
-            or (self.flags(rev) & revlog.REVIDX_RAWTEXT_CHANGING_FLAGS)):
+        if ((self._flags(baserev) & revlog.REVIDX_RAWTEXT_CHANGING_FLAGS)
+            or (self._flags(rev) & revlog.REVIDX_RAWTEXT_CHANGING_FLAGS)):
             return False
 
         return True
@@ -307,7 +307,7 @@
             return b''
 
         rev = self.rev(node)
-        flags = self.flags(rev)
+        flags = self._flags(rev)
 
         path = b'/'.join([self._storepath, hex(node)])
         rawtext = self._svfs.read(path)
@@ -381,7 +381,7 @@
     def iscensored(self, rev):
         validaterev(rev)
 
-        return self.flags(rev) & revlog.REVIDX_ISCENSORED
+        return self._flags(rev) & revlog.REVIDX_ISCENSORED
 
     def commonancestorsheads(self, a, b):
         validatenode(a)