diff -r f56873a7284c -r 4bd12c0f531e mercurial/configitems.py
--- a/mercurial/configitems.py	Fri Nov 25 15:14:40 2022 +0100
+++ b/mercurial/configitems.py	Mon Oct 17 16:26:16 2022 +0200
@@ -2075,6 +2075,7 @@
     b'revlog.reuse-external-delta',
     default=True,
 )
+# This option is True unless `format.generaldelta` is set.
 coreconfigitem(
     b'storage',
     b'revlog.reuse-external-delta-parent',