--- a/mercurial/help/config.txt	Wed Mar 27 19:34:10 2019 +0100
+++ b/mercurial/help/config.txt	Wed Mar 27 18:35:27 2019 +0100
@@ -1881,6 +1881,11 @@
     This option is enabled by default. When disabled, it also disables the
     related ``storage.revlog.reuse-external-delta-parent`` option.
 
+``revlog.zlib.level``
+    Zlib compression level used when storing data into the repository. Accepted
+    Value range from 1 (lowest compression) to 9 (highest compression). Zlib
+    default value is 6.
+
 ``server``
 ----------