--- a/rust/README.rst	Wed Sep 30 18:23:43 2020 +0200
+++ b/rust/README.rst	Wed Sep 30 18:10:53 2020 +0200
@@ -34,6 +34,15 @@
 One day we may use this environment variable to switch to new experimental
 binding crates like a hypothetical ``HGWITHRUSTEXT=hpy``.
 
+Special features
+================
+
+You might want to check the `features` section in ``hg-cpython/Cargo.toml``.
+It may contain features that might be interesting to try out.
+
+To use features from the Makefile, use the `HG_RUST_FEATURES` environment 
+variable: for instance `HG_RUST_FEATURES="some-feature other-feature"`
+
 Profiling
 =========